White rust? Rust isn’t white. Rust is orange!
The rust on an old car is orange. Fungal rust spores that grow on the underside of rose leaves are bright orange.
But white rust isn’t orange or fungal.
White rust, white blister rust, or blister rust, is a disease that attacks plants in the cabbage family, causing white blisters, deformed growth, and leaf loss. Wet leaves and cool temperatures are all that’s needed for white rust to take hold in broccoli, cauliflower, collards, radish, and turnips. Arugula and rapini are especially susceptible to white rust. Candytuft and shepherd's purse may also become infected.
White rust pathogen
White rust (Albugo candida) was thought to be a fungal disease until molecular research discovered that it is caused by tiny algae-like microbes, called oomycetes, that parasitize vascular plants. Downy mildews are also caused by oomycetes. The reproductive spores created by white rust can lay dormant in soil during the dry season, waiting for the rainy season.
White rust symptoms
As flowers and leaves are infected with white rust oomycetes, white blisters (pustules) form under the plant’s skin on the underside of leaves. These blisters contain baby oomycetes. When the blisters pop, oomycete spores take to the wind, infecting nearby plants. Spores are also transferred to other plants by splashing water from irrigation or rain. These pustules appear waxy and may be pinkish, at first. Upper leaf surfaces exhibit pale green or yellowish spots that can reach 1 inch in diameter. [This disease should not be confused with chrysanthemum white rust (Puccinia spp.), which is a fungal disease and appears as masses of black, brown, purple, orange, or yellow pustules. Chrysanthemum white rust is under a CA state eradication program.]
White rust controls
As far as I know, there are no resistant plant varieties available (yet). Commercial growers rely on fungicides to control this disease, but you can reduce the likelihood of infection simply by decreasing the amount of time leaves stay wet. Rather than overhead watering, use drip irrigation or soaker hoses. These methods save water, too. In severe cases, an area may need to be left fallow, or you can use some serious crop rotation.
Annual sowthistle is a common California weed that plays host to several garden pests.
While all weeds compete with your garden and landscape plants for sunlight, water, and nutrients, some weeds also carry diseases or provide habitat for pests. The annual sowthistle is one of those weeds.
Annual sowthistle (Sonchus oleraceus) is also known as milk thistle, hare’s thistle, soft thistle, and hare’s colewort. As a member of the sunflower family, sowthistles have a taproot and they produce a milky white sap (latex).
Annual sowthistle description
If you live in California, you’ve probably seen millions of these. Sowthistles can grow in only 1/2 an inch of soil, and they grow quickly. The cotyledons (seed leaves) are slightly football-shaped and less than 1/3 of an inch long. Early leaves are alternate, somewhat hairy, and feature margins (leaf edges) with backward facing teeth. Like dandelions, the stem is a smooth hollow tube. Mature leaves are a grayish blue-green. Upper leaves are smaller than lower leaves and there is no petiole (leaf stem). In many cases, the stem looks as though it is poking through the middle of the leaf, making them perfoliate. Lower leaves are deeply lobed and tapered. The flowers are yellow clusters that close at night (nyctinasty). These flowers matures into fluffy seed heads that blow in the wind, just like dandelions, but the seed heads are generally not a complete sphere.
Pests carried on sowthistle
Pests carried on sowthistle include lettuce aphids (Nasanovia ribis-nigri), lettuce root aphids (Pemphigus busarius), green peach aphids (Myzus persicae), and nematodes. Sowthistle should also be considered a vector of several different plant viruses. Pulling these weeds from your garden can break the disease triangle for many of these viruses, reducing or eliminating the need for more extensive treatments.
Pulling up seedlings as soon as they are seen is the easiest control. Unlike many other weeds, sowthistle does not regrow from root fragments. Since sowthistle only reproduces by seeds blown on the wind, preventing those seed heads from forming can significantly reduce your workload in the one run.
Luckily, sowthistles are easy to pull up.
No Southern supper would feel right without an occasional serving of collard greens. And no New Years Day celebration would be complete at my house without a big pot of Hoppin’ John, which combines rice, blackeyed peas, and collard, mustard, or turnip greens. Traditional folklore claims a bowl of Hoppin’ John on January 1st ensures prosperity in the coming year. It is certainly packed with protein, fiber, vitamins and minerals. Personally, I just love how it tastes! What many people don’t realize is just how healthy collards are for you, or how easy they are to grow at home.
Collards (Brassica oleracea, var. acephala) are biennial members of the cabbage family, along with broccoli and Brussels sprouts. In fact, collards, along with kale, are actually non-head forming cabbages! The name, collards, comes from the word colewort, or wild cabbage. Along with kale, collards are one of humanity’s oldest cultivated vegetables.
Heart-healthy collard greens
Collards contain more vitamins and minerals of any other vegetable, along with kale. Eating collards regularly is believed to reduce the chance of some types of cancer. A study published in Nutrition Research found that eating steamed collard greens was 13% more effective at blocking ‘bad’ cholesterol than the prescription drug Cholestyramine! Collard greens, being a dark leafy vegetable, also contain high levels of Vitamins A, K, and C, along with manganese, dietary fiber, and calcium. Google collard greens and you are sure to see them listed frequently in the world’s healthiest foods, so why aren’t they growing in everyone’s garden?
Collards taste funny to some people
Collard greens contain so much calcium that some people find the taste bitter. You can lose or soften some of that bitterness with these cooking tips:
Unlike spinach, which can only tolerate gentle cooking, collards often need to be cooked for 15 to 20 minutes to soften completely. The liquid left behind after cooking collard greens is called pot liquor, or potlikker. Frequently seasoned with salt, pepper, salted pork or smoked turkey, pot liquor makes an excellent broth, made even better when sopped up with a piece of freshly baked cornbread. So, let’s get some of these healthful, flavorful plants growing in your foodscape!
How to grow collards
Collards can tolerate temperatures as low as 5°F, but they will bolt in our California summer heat. Bolting does not affect leaf flavor (and it can give you seeds for your next collard crop), but collards are generally a cool season crop. A light touch of frost actually sweetens the flavor of collard greens. Here in the Bay Area, collards can be planted February through April, and again in September and October. These plants can get relatively large, with broad, waxy, dark green leaves. They prefer lots of sunlight and need plenty of organic matter in the soil. You may need to acidify the growing area, as collards perform best in soil with a pH of 6 to 6.5.
Plant collard seeds 1/4 to 1/2 inch deep. You can start seeds in cell flats and then transplant into your garden or foodscape. [Since seed packets nearly always contain far more seeds than you will ever need or use, hold a seed swap with friends and neighbors!] If you direct sow, plants should be thinned to 18 to 36 inches apart, depending on the variety. Side dress plants with aged compost or manure every 4 to 6 weeks, and mulch around plants to reduce competition from weeds and to maintain moisture levels and temperatures. Collards have a shallow root system and water-stressed collards taste far more bitter than properly irrigated plants.
Collard pests and diseases
As with other members of the cabbage family, collards are frequently fed on by aphids. You can blast these pests off of plants with a powerful stream of water from the garden hose, or you can apply insecticidal soap. Cabbageworms, slugs, and cabbage loopers can be handpicked. [I feed them to my chickens.] Flea beetles, bagrada bugs, whiteflies, and cabbage root maggots can also be a problem. Research conducted at UC Davis found that flea beetle and aphid populations can be reduced when collards are interplanted with beans. They found that the same was true for weeds, but I’d rather have beans than weeds! Apparently, the mixed plantings work better at attracting parasitic wasps, making crops harder to find, and by providing other food sources for the pests.
Diseases that affect collards include white rust, blackleg, cabbage yellows, and clubroot. You can reduce the likelihood of these diseases occurring by rotating crops in the cabbage family into a different growing space each year.
Most collard varieties are ready to harvest in 55 to 75 days. Collards are one of those cut-as-you-go crops. Just keep picking outer leaves, as you want them, and the paints will continue producing more for several months. It is a good idea to allow plants to reach a height of at least 10 inches before harvesting leaves. If you find that you have more collard greens than you can eat, you can always cook them and then freeze them, for longer storage. Your friends and neighbors may appreciate some, as well!
Collards are large, attractive plants. They do not need to be sequestered into traditional garden rows. Find a nice, sunny spot in your landscape and make it home to your very own collard plant!
Why do people paint their trees white?
Is it a rural fable? A picket fence prank? Or, is there real science behind the idea of painting tree trunks white?
It ends up, there are very good reasons for painting both the trunk and the upper sides of exposed branches with a certain type of white paint to protect against sunburn, pests, and disease.
Benefits of whitewashing
An annual application of whitewash reduces sunburn damage by reflecting sunlight away from the tree. Sunburned bark frequently splits and curls, providing easy access for numerous pests and diseases. This is especially true for borers, such as shot hole borers and flathead borers, as well as moth larvae, beetles, and horntails. Whitewashing has also been found to discourage rodents, such as voles, mice, and rabbits, from gnawing on the trunk. The paint also helps protect against frost damage.
What type of paint should be used?
Whitewashing is one of those ‘too much of a good thing is a bad thing’ situations. Using enamel (the wrong paint) can kill young trees. So can using latex (the right paint) if it is undiluted. Traditionally, whitewash was made from slaked lime and chalk. It was a poor man’s paint that tended to rub off onto your clothing if you brushed against it. While this material has mild antibacterial properties, mixing it can be messy.
When you head to the paint store, or go digging around in your garage, make sure that you only use interior latex, and not enamel or exterior latex. Exterior paint may contain harmful additives. The important thing to look for is the "VOC" - these letters stand for "volatile organic compounds". These compounds can be dangerous to trees and humans. Paints listed as being VOC-free or being low in VOCs are better choices, health-wise.
Whitewashing should only be done with interior latex paint that has been diluted with water. Use a mixture of half water and half interior latex paint.
How much of a tree should you paint?
Newly planted bare root trees should be painted completely. To protect mature trees, pull the soil away from the trunk to a depth of 2 inches and paint the entire surface to a height of 2 to 4 feet, depending on the tree. After the paint has dried, put the soil back in place. The upper surfaces of branches that are exposed to sunlight should also be painted.
When should I whitewash my trees?
Here in San Jose, California, whitewash is applied after dormant pruning and dormant oil spraying are complete. This is usually in January or February, but you can whitewash your trees at any time that will allow the paint to dry. After it has dried, you can give your trees added protection from crawling pests with a sticky barrier.
The paint and the sticky barrier will need to be reapplied each year, to maintain their usefulness.
Currants are a refreshing berry used to make jams, jellies, pies, and wine, but currant borers can really put a dent in your crop.
In California, the invasive currant clearwing moth (Synanthedon tipuliformis) makes its appearance each April, laying eggs in bark crevices, at old pruning cuts, and in narrow branch crotches. While individual moths only live one week, overlapping generations can extend egg-laying through August. These pests bore into the canes of currants, and sometimes blackberries.
Currant borer description
Currant clearwing moths look more like wasps than moths. They have a long, narrow black body with yellow stripes. Males have four stripes; females have three. Wings are triangular and mostly clear, and the front and back wings are hooked together. Legs and antenna are long, and moths have a slightly paddle-shaped rear end. The wingspan is 1/2 to 3/4 of an inch wide. Larva are white to yellow, with brown head and legs, and a dark dorsal line may be visible. Larva look much like the American plum borer. Pupal cases are reddish brown and 3/4 of an inch long. Eggs are pale pink to red and very tiny.
Currant borer damage
When the eggs hatch, larva chew entry holes in canes, burrowing into the cambial tissue and sapwood. Here, they will feed on sap and vascular tissue for the rest of the summer, and then overwinter within the canes. In March, they will resume feeding, going through several instars, before entering a pupal stage. All this boring and feeding can girdle branches, causing twig and branch dieback. It also restricts the growth of infested plants, resulting in fewer blooms (ergo, less fruit). You may be able to see sawdust-like frass mixed with sap oozing out of entry holes, and longitudinal scars on infested twigs and branches.
Currant borer controls
Once a branch is infested, it should be removed and destroyed, or thrown in the trash. Severely infested plants should be removed completely. Once borers are inside a plant, there isn’t much you can do. Some people try shoving wires into entry holes, trying to stab the larva, but this is only marginally effective. Woodpeckers enjoy catching adult moths on the wing and braconid wasps parasitize these pests. There are also some beneficial nematodes that are available commercially. I’m not sure which species of nematode will work against currant borers, but you basically inject the live nematodes into the borers’ holes and spray the branches with nematodes in solution. Nematodes are fiddly and I have not had good luck with them, but they may work for you. Rather than losing valuable plants, it is far easier to prevent borer infestations int the first place.
Healthy plants are better able to protect themselves against infestation, and rapid growth tends to make stems susceptible. Caring for your currant plants in a way that keeps them healthy and growing at a steady pace, rather than overloading them with fertilizer for faster growth, is the best way to prevent infestations. Also, avoid water stress with regular irrigation, especially during the peak of summer. Whitewashing the trunks of mature tree-trained currants with a 50:50 mix of water and latex interior paint can help reduce sunburn damage, which is more susceptible to infestation.
Pheromone traps can be used to monitor for this pest. Just remember that the down-side of using pheromone traps is that they end up attracting pests from a greater distance. According to the U.S. Dept. of Agriculture, insecticides should be applied 7 to 10 days after the first male moth is captured in a pheromone trap. If you decide to use an insecticide, please, Please, PLEASE, follow the directions on the label exactly. Insecticides are poisons.
Finally, regularly inspecting your currants and blackberries for signs of infestation can give you a unique opportunity at borer control. Just before clearwing borers emerge, they have a habit of pushing themselves halfway out of their tunnel and just sitting that way for a bit - catching their breath, I assume. So, look for areas of damaged bark and frass. If you see a borer half-way out of a twig, cane, or branch, help it out the rest of the way and then feed it to your chickens or stomp on it.
How do you choose which plants to grow?
Seeds catalogs and garden centers offer us more plants to choose from than have ever been available before. It can feel overwhelming. All too often, we end up with plants that don’t grow as well as we would like, or that take more care than we have time to give. This guide will help you select plants that will grow well, while not using up every hour of your day.
Step 1: What are you already growing?
Before you add something new, it helps to identify what you already have. Established perennials, sun exposure, and soil health will often dictate the conditions available for new plants. Trees and shrubs that are already in place need to be taken into account. They may provide the perfect protection for a collection of shade-loving plants, while sun-loving varieties would wither in theat shade. Speaking of shade, just how much sun does each area of your garden get each day? It changes with the seasons. Knowing just how much sun each area gets can help you select plants more likely to thrive. Most garden plants need 6 to 8 hours of full sunlight each day to be healthy. Also, keep in mind that some plants use a form of chemical warfare, called allelopathy, to reduce competition from neighboring plants. Learning a little about allelopathy can increase the likelihood that your plants will thrive.
I’ve said it before and I’ll say it again: Take a soil sample and send it to a local, reputable lab. [Over-the-counter soil tests, with those little plastic tubes, are not accurate enough to be useful.] The results of your soil test will help you prepare better for those new arrivals, as well as help your established plants. Wood chips, mulch, or a ground cover may be just what is needed. Here, in San Jose, California,, acidification is often recommended for many popular plants.
Step 2: What do you want from your garden or landscape?
For me, the answer to that question is simple - I want edible plants that my family will enjoy eating. Your reason for gardening may be something entirely different. Do you want an herb garden? A flower garden? Do you want maintenance-free plants that will look good year round? Taking the time to decide what you want from your landscape or garden design through each season will help you select the best plants. I use my shopping list. If I write a fruit or vegetable on my shopping list with any frequency, I ask myself if it is something I can grow at home. Nearly always, it is, so I do! [If you are at a loss on this one, take a look at the list of garden design prompts, below.]
Step 3: Zones, pathogens, and cultivars
Before shopping for plants, you should also consider your region. If you live in the United States, you can use the U.S. Hardiness Zone map. This tells you which growing zone you are in. Growing zones are based on average annual winter temperatures and they help you select which plants will thrive in your location. You should also check out resources from your local County Extension Office. They can often provide you with information about common pests and diseases, specific to your area. You can use this information to select cultivars that are resistant to the pathogens common to your area. Also, avoid installing non-native invasive plants. While reputable plant sellers are taking these plants off their shelves, not all sellers care.
Step 4: Start shopping and planting!
Finally! Now that you know what you are working with, what you want, and what will grow well in your area, you can finally start shopping for or collecting your new plants! Remember, catalogs and garden centers are not your only source for plants:
When shopping for new plants, watch for signs of pests or disease. You don’t want to introduce a new problem along with the plant. Many plant pests and diseases are brought in on contaminated soil and plants, which is why a quarantine period is such a good idea. It allows you to break the disease triangle before it affects the rest of your garden.
Garden design prompts
Sometimes, we just don’t know where to begin. I think this is especially true when we have an overwhelming number of options. If you have absolutely no idea what you want to do with your landscape or garden design, see if any of these themes spark inspiration:
Rather than grabbing the first plant that catches your eye, taking the time to learn about what your microclimate has to offer and deciding what you want from your landscape or garden design can help ensure that the plants you actively choose to add will be appropriate, rewarding, and healthy.
Native plants are those that evolved, over thousands of years, to live in relative balance with local soil, climate, plants, animals, and insects.
These are not plants from other regions or other continents. They are often not even plants native to nearby counties. These are not plants that were developed in a laboratory. There’s nothing wrong with all those other plants; it simply means that they are not native to a specific location.
While it is always a good idea to select plants appropriate to your Hardiness Zone, that isn’t the same thing as growing native plants. Here, in California, many of us grow plants suited to a Mediterranean climate. Those plants are not necessarily native to where we live.
Benefits of native plants
Native plants are perfect for busy (or lazy) gardeners and home owners. Once installed, these plants already have everything they need in a landscape:
Installing native plants reduces your work load and promotes a healthy environment over the long haul. While non-native plants may look appealing, they often require more work, water, and other resources. So, how does a gardener go native?
Going native doesn’t mean you have to stop growing your grandmother’s heirloom tomatoes or that delicious basil. It simply means using native plants as your first choice. Hardcore enthusiasts insist on growing nothing but natives. Personally, I find that much commitment too limiting. Instead, I look for a balance of natives and edibles. You can find local information about native plants from your County Extension Office. If you live in California, the Theodore Payne Foundation and the California Native Plant Society provide a wealth of information. Here are some tips for gardeners looking to add native plants:
Edible native plants
Nearly every region offers native plants that are edible. You can search online for lists of edible plants native to your area. California is home to hundreds of edible native plants. Here are some of my favorites:
Here in California, drought is never far from our thoughts. Water-hungry plants are not well suited to our scorching hot summers. Native plants, such as salvias, have evolved natural water conservation methods. You can also add native plants to a rain garden or a swale, to create a natural watershed that slows rain water long enough for more of it to stay in the soil for later use. If you grow native plants for no other reason than water conservation, you will be doing yourself and the environment a favor.
Growing native plants allows you to conserve resources, promote biodiversity, and maintain an attractive landscape, all while growing some, or all, of your own food right at home.
Each kernel of corn is a specialized type of fruit, called a caryopsis. So are rice, oats, barley, and wheat.
Fruits are the seed-bearing structure of angiosperms (flowering plants), made from the ovary (pericarp) of a fertilized gamete. Fruits taste good because that makes them more likely to be eaten, spreading seeds far and wide. We are all familiar with fruits. Apples, peaches, olives, and avocados are all fruits, but so are cereal grains.
Unlike apricots and nectarines, which have thick, juicy fruit walls, cereal grains have a very thin, dry fruit wall, or husk. A caryopsis is a simple fruit. This means they develop from a single pistil. Because there is no seam to split open and release the seed within, it is called indehiscent. Botanically, the outer skin of corn kernels and grain seeds is the pericarp, or husk. The husk is firmly attached to the seed coat. That is why special milling processes must be used to get at those edible seeds.
Hulls, husks, and seed coats
Hulls and husks are the same thing - most of the time. Looking at an ear of corn, the leafy outer coating is called a husk. Botanically, a husk, or hull, is another name for a seed coat. It can also refer to a pea or bean pod. These outer coats are removed using a process called threshing. Threshing is a brutal process (if you’re a grain). Mules and other livestock have been used to walk in circles on the grain, breaking it free of its hard outer coat. In some regions, grain is spread on roads to be threshed by cars and trucks. Traditionally, the dried fruit husk was removed using a flail.
While blossoms and blooms and weeds and new seedlings have been telling us for days or even weeks, it is finally official. Spring has arrived! [Or, autumn, if you live in the southern hemisphere.]
Spring equinox is the moment when the Sun passes the Earth’s equator, moving from south to north, with no apparent tilt to the Earth axis.
Normally, we feel the Earth’s tilt as different seasons. Half of our trip around the sun is spent tilted slightly away from the sun (colder weather) and the other half is spent with a similar tilt toward the sun (warmer weather). Today, because we see the sun passing our equator, day and night are the same length. Sort of. That is why it is also called the spring equinox. I say ‘sort of’ because the day will actually be longer than the night. This is because of the sun’s light being refracted through the atmosphere before and after it has risen and set. If you want to know more about the Earth’s tilt and seasons, check out my post on winter solstice.
So, you’ve been waiting for months, browsing seed catalogs and dreaming of all the plants you want to try this year, along with some old favorites. Spring is a busy time in the garden, to be sure, but don’t be hasty. Don’t let all those visions of a summer harvest cloud your view. While the Bay Area’s last frost date was nearly a week ago, I woke to see frost all over my garden only yesterday morning. Nature does not obey our rules. We must keep our eyes and ears open and be aware of what is happening in our microclimate. That being said, it is now time to start planting! Or, is it?
Before you start planting….
Speaking of frost, what about those plants that were damaged by frost over the winter? All that damaged plant tissue should be removed now to reduce rot in the garden. It makes things look nicer, too. But are your tools sharp enough for the job? A quick fix with a file or sharpening tool makes the job so much easier, and a little 3-in-1 oil will protect those tools from moisture damage. And are your planting beds and containers actually ready for plants? Adding some aged compost before you start planting will do your plants and your soil a world of good for the upcoming growing season. While you’re outside, take a look at your citrus trees. Do they need pruning? Now is the time to do it. And, while you’re at it, keep a look out for mummies. These fungal factories can contain millions of spores. This is also the time to watch for things like mummy berry and black spot. Recent rains make this a time of fungal growth. Slugs and snails like it, too, so be prepared!
Seeds, starts, and transplants
Your garden is finally ready for planting! You can still plant winter crops, such as beets, broccoli, cabbage, carrots, cauliflower, chard, lettuces, spinach, bok choy, fennel, kale, mustard greens, parsnips, and turnips. And it’s not too late to start that asparagus bed! You can now plant herbs, such as cilantro, dill, and parsley, but hold off on basil, until things warm up. You can now plant potatoes and radishes, too. More delicate plants, such as tomatoes and peppers can be started in pots, but only if you have a place where they can be protected from nighttime temperatures.
Hold off on beans, corn, cucumbers, melons, squash, sweet potatoes, until April or even early May. Be sure to use plant markers, as you start seeding your garden. Things can quickly get out of hand, if you forget where you put everything! If you have some spare time on your hands, as it rains, use that time to study up on your plants: what are their thinning requirements, sunlight needs, estimated mature size, irrigation and fertilizing needs? That sort of stuff. Talking about rain…
A word on drought
While San Jose and northern coastal California areas are not currently under drought status, many other parts of the state, and an estimated 32 million residents, are. And, let’s face it, the days of wasting water are over. If you haven’t yet, use today’s spring equinox as a turning point in how you look at water. Turn off faucets. Inspect irrigation systems. Use a bucket to collect shower water as it heats up. Install drought resistant native plants. Stuff like that.
For the next three months, each day is going to give you just a little more daylight ~ what will you do with yours?
We don’t know why certain flowers tuck themselves in at night, or why some leaves fold themselves together as the sun sets, but we know how they do it. These openings and closings of petals and leaves is called nyctinasty [nik-TIN-as-tee]. Nyctinastic movements are also called sleeping movements.
Options in plant movement
While plants are not free to get up and walk around, they do have options when it comes to movement. Some plants follow the sun’s movements across the sky, in a behavior called phototropism. There are also rare individuals who exhibit skototropism by moving away from sunlight. Note that both of those words end with -tropism. Movement is tropic [TRO-pic] if it is in reaction to a source of stimulus. Tropic movement is nearly always growth related and it is dependent on the direction of the stimulus. If a plant’s reaction is independent of the stimuli’s position, it is called a nastic movement. Nastic movements may or may not be growth related. If you see a plant behavior word that ends with -nasty, you will now know that it is a nastic behavior. Nyctinasty is one of those words.
Latin bed times
We all have our bedtime routines. Some plants do, too. These routine behaviors are called nyctinastic. You just learned that -nastic means movement independent of a stimuli’s position. When it happens because of nighttime, we add the Latin prefix nyct-, which means ‘at night’. Put the Latin for non-directional reaction to nighttime together and you get nyctinasty.
Why do flowers close at night?
We don’t know. Charles Darwin thought that nyctinasty was used to protect against freezing. Some scientists theorize that it has to do with pollination and reducing competition, or protecting nectar from bacteria and fungal spores. Other possibilities include saving up aroma molecules for when they will be most effective, energy conservation, or as a means to prevent pollen from getting wet. Wet pollen is heavy and insects are less likely to carry as much, potentially reducing pollination rates. Yet another theory is that nyctinastic flowers and leaves close up shop to prevent being eaten by nighttime herbivores. The truth is, we don’t know why. We do know, from laboratory tests, removing the gene that causes nyctinasty results in plants with smaller leaf areas and reduced biomass. We may not know why they do it, but we do know how they do it.
How flowers and leaves open and close
Several different flowers, such as tulips, dandelions, crocuses, and daisies, and the leaves of many legumes species, open each morning and close each night. Some flowers, particularly the Kalanchoe genus, grow new or longer cells each morning, on the inside of the flower, to open it, and on the outside of the flower each evening, to close it. Other flowers, and most nyctinastic leaves, rearrange fluids within the plant to cause these movements. This movement of fluids is a reaction to changing temperatures and light frequencies.
Movements of liquid and light
Nyctinasty is triggered within a plant in response to changes in external light, temperature, and humidity, and an internal circadian clock. As the sun sets, light frequencies change and temperatures drop. The shorter wavelength and higher deflectability of blue light gives way to longer, less readily deflected red wavelengths, and lower temperatures. The reduction of blue light triggers blue-green pigments (phytochromes) to rearrange potassium ions within the plant. This rearrangement of ions pulls water along with it, causing turgor. Turgor refers to rigidity that is normally caused by the presence of fluids.
So, as dawn arrives and temperatures start to rise, interior cells grow faster, or are inflated with water, to push open your flowers. At days end, outer cells grow longer and faster, or internal cells are deflated, and the flowers close for the night. This is nyctinasty.
Endophytes are tiny heroes of the garden.
You rarely see them with the naked eye, but most of these tiny organisms work hard to protect our plants.
What are endophytes?
The word ‘endophyte’ literally translates as ‘in the plant’ (‘endo’ = within; ‘phyte’ = plant). Endophytes are tiny organisms that live inside plants, for at least part of their life, without causing disease. In most cases, they provide a benefit to the host. The plant returns the favor by providing the endophytes with carbon [sugar]. Endophytes can be fungal, bacterial, or viral, or they can be other plants. Endophytes are everywhere and they can occur in any place within a plant.
Some endophytes grow between plant cell walls, while others live inside plant cells, and they tend to grow at the same rate as their host. Researchers have learned that plants and their endophytes use chemical signals to communicate with each other. These communications determine which helpful chemicals and what quantities are needed by both sides of the arrangement.
The science behind endophytes is relatively new. Because of this, the definitions are still being sorted out. Some scientists include parasitic and pathogenic organisms as endophytes, while others focus on the beneficial, or mutualistic forms. That’s where I stand, for now. There are several different ways that endophytes help their host plants.
Certain endophytes help plants get the food they need. The rhizobium bacteria that helps legumes fix atmospheric nitrogen is a type of endophyte. Other endophytes break down rock phosphate within the soil, making it absorbable to plant roots. Some scientists categorize mycorrhizae, or root fungi, as a type of endophyte, while others do not. [Isn't it exciting, being on the crest of new scientific research?]
Endophytes have been shown to enhance overall plant growth. They do this by improving a plant’s tolerance of abiotic stresses, such as drought, heat stress, water stress, salinity, and poor soil. When allowed to grow naturally, these mutually beneficial arrangements make both parties stronger. Unfortunately, the use of fungicides interferes with endophyte development. Also, the use of fertilizers reduces a plant’s reliance on its resident endophytes. This is, theoretically, fine, as long as the fungicides and fertilizers continue to be supplied. As soon as these artificial treatments are withdrawn, however, host plants are left with less food and protection.
Commercial agriculture is slowly coming around to the long term benefits associated with these natural arrangements, but you can take advantage of it in your own garden right away by avoiding the use of chemical fertilizers and fungicides.
Did you know that when you inoculate legumes, you are putting endophytes to work for you in the garden? Now you know!
Four-leaf clovers may bring good luck, but some clovers can be a real pain.
The word clover actually refers to three different genera of plants: Trifolium, Medicago, and Melilotus. There are over 300 species of clover and they are found throughout the Northern Hemisphere and occasionally in South America and Africa. Depending on who you ask, clovers can be beneficial ground covers or pesky weeds.
Clovers are also called trefoils because they nearly always have leaves in groups of three. [A four-leafed clover is said to be quatrefoiled.] Clovers are legumes, along with peas, beans, and alfalfa. This means they have a symbiotic relationship with certain Rhizobium bacteria that allows them to fix atmospheric nitrogen and use it to grow. For the most part, clover seeds start to germinate in the fall, and continue until temperatures rise above 60°F. Clovers are classified as annual, sweet, or perennial.
Annual Clovers grow mostly in a prostrate manner from a single taproot. They feature tiny yellow flowers. CA burclover (Medicago polymorpha) and black medic (Medicago lupulina) are turfgrass weeds, while little hop clover, also known as lesser trefoil or shamrock clover (Trifolium dubium) is frequently added to turfgrass mixtures.
Sweetclovers are upright annuals or biennials that grow from 2 to 5 feet tall. White sweet clover (Melilotus alba) and yellow sweetclover (Melilotus officinalis) often turn up in ornamental plantings.
Perennial clovers are often planted on purpose to reduce the need for nitrogen fertilizers. White clover (Trifolium repent) and strawberry clover (Trifolium fragiferum) both have the compound flower heads common to these clovers.
Adding clover as a ground cover or a green manure can mean future plantings will thrive or, as the saying goes, “They will be as happy as a pig in clover.” Of course, bees love clover flowers, so be sure to plant your clover where you are less likely to step on a bee.
If clover is causing problems in your garden or landscape, the best control methods are hand-pulling, hoeing, and mulch. The mulch needs to be 4 to 6 inches deep to block clover. Clover seeds are very rugged, so composting and solarization are generally not effective controls.
If you have bright green clover popping up in a yellow lawn, your soil is probably low on nitrogen.
Did you know that a group of clovers is called a cluff? I didn’t either.
Bermuda buttercup is a sunny yellow flower that appears in San Jose, California, each winter and spring.
Originally planted as an ornamental (oops), we now know that this South African invasive weed has the potential to make life quite difficult for our native species.
Also known as sourgrass, Buttercup oxalis, Oxalis cernua, or simply oxalis, this low growing perennial is difficult to control. [The oxalis family is actually quite large and we will discuss that another day.] Close cousin to creeping woodsorrel, oxalis contains relatively high levels of oxalic acid, which is what gives it its sour taste. That is also why they should not be consumed in large quantities by livestock or your backyard chickens.
Bermuda buttercup description
Three heart-shaped leaves that resemble clover make Bermuda buttercup (Oxalis pes-caprea) easy to identify. Most Bermuda buttercup plants have a loose rosette of basal leaves and tall stems, usually a foot tall, that feature bright yellow, 5-petalled flowers. You may see brown or purple spots on the leaves. Tiny bulblets form around the stem and more bulbs develop underground. Bermuda buttercup plants produce an average of 10 to 20 bulbs each year. Bermuda buttercup also spreads using runners and through contaminated soil.
Controlling Bermuda buttercup
This weed is very difficult to control, once it takes hold. Pulling the weeds does little to eliminate them, since the bulbs left behind are perfectly capable of starting the whole process over again. While Bermuda buttercup is rarely a problem in lawns, in can quickly become a serious problem in landscapes and home gardens. In the past 10 years, this invasive weed has choked out many native plants.
Homeowners are urged to eradicate this weed, to help prevent its spread into wildlands, where permanent damage may occur. Use the methods below to control Bermuda buttercup on your property, and please educate your neighbors, before it is too late.
You will rarely hear me suggest herbicides, but this is one case where their proper use may be warranted. Always read the label and follow directions exactly. Seriously.
If you really must have pretty yellow flowers in your garden or landscape, please don't let it be Buttercup oxalis.
While these furry, clumsy, easy-going pollinators can sting you, repeatedly even, they generally choose to ignore us. [Unless they get caught in a certain young girl’s unruly long hair. Believe me. I speak from personal experience.]
The name bumblebee, or bumble bee, comes from the characteristic buzz (bumble) of this gentle pollinator. Before it was called bumblebee, it was known as a ‘humblebee’ and before that a version of a ‘clumsily flying buzzing beetle’ or ‘dumbledor’ was used. [I’ll bet you weren’t expecting that one!]
Charles Darwin had this to say about bumblebees in his book, On the Origin of Species (1859):
I have [...] reason to believe that humble-bees are indispensable to the fertilisation of the heartsease (Viola tricolor), for other bees do not visit this flower. From experiments which I have tried, I have found that the visits of bees, if not indispensable, are at least highly beneficial to the fertilisation of our clovers; but humble-bees alone visit the common red clover (Trifolium pratense), as other bees cannot reach the nectar.
Bumblebees really are clumsy fliers. They bump into stems, leaves, and branches quite frequently. Research conducted at the California Academy of Sciences and UC Davis explored how bumblebees are able to withstand the frequent collisions they experience each day. When I say frequent, I mean once a second, on average.
Cousin to honeybees (Apini), orchid bees (Euglossini), and stingless bees (Meliponini), bumblebees (Bombini Bombus) have pollen baskets on their legs, making them all corbiculate. Fossil evidence of the common ancestor to these beneficial insects dates back 100 million years. Bumblebees have been around for 25 to 40 million years, depending on who you ask.
Bumblebees are more commonly found in higher latitudes and higher elevations than other bees. There are even two species found in the Arctic! This may be due to their fur coats, but scientists explain that bumblebees are able to regulate body temperature, using the sun’s radiation and ‘shivering’ to generate heat. Unlike other bees, bumblebee queens are known to incubate their eggs.
Like other insects, bumblebees have a three part body made up of the head, thorax, and abdomen. The head features two compound eyes and three primitive eyes, mouthparts, and antennae. Female bumblebee antennae have 12 joints, while males have 13. The thorax is where the wings, legs, and wing muscles are found. The abdomen contains the digestive and reproductive organs and the stinger.
Bumblebees have two pairs of wings, a fore wing and a rear wing. The wings connect to muscles that are attached to the inside of the plates that make up a bumblebee’s exoskeleton. A waxy substance is secreted from glands and discharged from between the plates. It looks a lot like dandruff. Bees groom the wax into clumps and use it to build honey pots, egg coverings, and as nesting material. Bumblebees do not have ears. We do not know if they can sense sound waves through the air. They do seem to be able to sense vibration through other materials, such as the ground.
Unlike the oblong honey bee, or the shiny black female carpenter bee, your average bumblebee looks round and furry. This is because they are covered with very soft, finely branched bristles, called setae. Bumblebees can usually be differentiated from golden male carpenter bees by the presence of contrasting bands and other markings. This aposematic coloration serves as a warning to would-be predators. Some other insects, such as hoverflies, mimic and are protected by this coloration. This is called Batesian mimicry. Bumblebees come in a variety of sizes, ranging from 1/2 an inch, up to one-and-a-half inches long. [Don’t worry, that big one lives in Chile and is affectionately referred to as a ‘flying mouse’ - okay, maybe not affectionately.]
Bumblebees store fat in their body. This fat is used up during hibernation. Bumblebees do not use the bee dances common to honey bees, but they do exhibit social learning. Youngster bumblebees are frequently bumped off of favored flowers by more mature bees. In a lab experiment, bumblebees were taught to move an object in exchange for a reward. Untrained bees who observed the task-reward process learned it more quickly than those bees who observed the same exchange performed by an inanimate object. In fact, observer bees consistently improve on the methods used initially, implying at least some level of cognition.
Most bumblebee species are social insects. They live in relatively small colonies, led by a queen. Honey bee colonies hold 10 to 60 thousand workers, during peak honey production, while a bumblebee colony may only contain 50 to 1,500 individuals.
Bumblebee nests are first constructed by an over-wintered queen. After collecting pollen and nectar from flowers and finding a suitable nesting site, the young queen will build wax pots to store food, and wax cells to receive her eggs. As the eggs hatch into larvae, the cells are expanded into a lumpy mass of brood cells. Nesting sites can be in or on the ground, or in tussock grasses, depending on the species. Bumblebee nests are a food source for badgers and other insectivores. Bumblebees normally range only a mile or so from the nest.
A queen bumblebee performs a mating flight before retiring to her nest. There, she will ‘decide’ whether or not to use the collected sperm to fertilize each egg she lays. Unfertilized eggs develop into males. Fertilized eggs grow up to be hormonally suppressed worker females or fertile queens. Mature males are forced out of the nest by the females. Males and new queens live independently from the colony, sleeping in flowers or holes in the ground.
Bumblebees feed on nectar, and pollen is collected for the young. Bumblebees lap up nectar with a long, hairy tongue, called a proboscis. The tip of the tongue may also be used as a straw. Because the tongue is so long, bumblebees are able to gather nectar from (and pollinate) deeper flowers than honey bees, which have shorter tongues. When bumblebees fly, the proboscis is often folded under the head. Some bumblebees feed on flowers from above, the way other bees and hummingbirds do, while other ‘rob’ the nectar by cutting a hole in the base of the flower. It is called ‘robbing’ because this behavior avoids pollen transfer. [The metabolic rate of bumblebees is 75% higher than a hummingbird’s.]
Some species of bumblebee leave a scent marker behind on a flower, after it has fed. This marker deters other bumblebees from feeding on that flower, until the marker fades. Once a bumblebee has eaten its fill and collected all of the nectar it can carry, it returns to the nest and deposits its riches in brood cells, for the young, or in wax cells, for storage. Unlike honey bees, which process nectar into honey, bumblebees store it as-is.
Bumblebees as pollinators
Bumblebees are powerful pollinators. As they feed, moving from flower to flower, they collect and deposit pollen. Bumblebees are commonly used in greenhouse tomato production. They are fed sugar water so that they do not need to harvest nectar, and can focus exclusively on pollen.
[Did you know that pollen is left behind at each flower because the act of flying causes the bee to build up a static charge? The plants, being rooted in the ground, are, well, grounded. The electrically charged pollen grains on the bee are attracted to the stigma, which happens to be the best grounded part of a flower, while the flower’s grounded pollen is attracted to the bee’s statically charged body. How bizarre and amazing is that?!!?]
Bumblebees also pollinate plants by a method called buzz pollination, or sonication. They do this by disconnecting their wings from their flight muscles and vibrating their flight muscles at a frequency very close to middle C. [The frequency varies depending on plant species.] The force generated during sonication can reach 30 Gs, which is almost more than a human can tolerate! This vibration causes a flower’s pollen to burst forth. This method is particularly effective on blueberries and members of the nightshade family, such as tomatoes, tomatillos, and eggplant. Sweat bees, carpenter bees, and stingless bees sonicate, but honey bees do not. PBS has an amazing video of buzz pollination.
California bumblebee species
There are over 250 species of bumblebee worldwide and 26 species in California. There used to be 14 native bumblebee species in the Bay Area. Now there are only a handful. This is especially unfortunate when you realize that native bumblebees are responsible for pollinating 42% of all native California flowering plants, according to UC Davis entomologist Robbin Thorp. Currently in the Bay Area, you may see:
These bumblebee species have not been seen in the Bay Area in recent years:
Cuckoo bumblebees, or brood parasitic bees, do not live in colonies. Instead, cuckoo queens will invade a nearby bumblebee nest, kill the queen, and then start laying their own eggs, which end up being cared for by the murdered queen’s workers. [You can tell the difference between a cuckoo bumblebee and a social bumblebee by looking closely at the back leg: nesting female bumblebees have a pollen basket, which is bare and shiny, whereas a cuckoo bee hind leg is covered with hairs. They transport pollen by wedging it between the hairs.]
Like the European honey bee, bumblebee numbers are declining. This is largely due to habitat loss, pesticide use, and the mechanization of agriculture. You can counteract some of these effects by planting flowers that attract and provide for bumblebees.
Bumblebees are attracted to flowers by both sight and smell. They seem to prefer flowers that grow on spikes, such as salvia and lavender. This may also be because these flowers tend to be blue, purple, or white, favorite colors of bumblebees. Bumblebees are also attracted to members of the sunflower family. The most important consideration when planting to attract bumblebees is that the stems are sturdy enough to support these heavy pollinators. Bumblebees can also see a flower’s temperature, as well as its electrical field.
You may very well already have plants that attract bumblebees. If you allow your kale and other cabbage family members to bolt in early spring, bumblebees will take advantage of the blooms, and you will add these plants to your foodscape as seeds are dispersed later in the season. Other popular flowers that attract bumblebees include anise hyssop (Agastache foesniculum), guaras (Guara lindheimeri and other cultivars), bog sage (Salvia uliginosa), Mexican sage (S. mexicana) and many members of the mint family, including basil, thyme, sage, and rosemary. Native plants, such as manzanita, ceanothus, CA buckwheats, penstemons, currants, and gooseberries will also attract and provide for these hard working beneficial insects.
Bumblebees are housing opportunists. They build nests in upturned planter pots, abandoned mouse burrows, and under boards. If you have a square foot of bare, undisturbed soil and the right flowers, you are pretty much guaranteed a visit.
The U.S. Forest Service offers a comprehensive guide to California bumblebees and a nice poster of western bumblebees with dietary notes. You can also learn more about bumblebee conservation from the Xerces Society.
Pine trees, junipers, the mighty redwood are all members of an ancient family, the conifers.
Conifers have been around for 300 million years. They were the dominant plant of the Mesozoic Period, or the Age of Reptiles, and a primary food of many herbivorous dinosaurs.
Adding conifers to a landscape is an excellent way to create year round color. They make excellent anchor plants and they often create food and habitat for wildlife, increasing your garden’s biodiversity.
All conifers are perennial woody plants that get thicker and larger with age. The secondary growth that allows a giant redwood to attain its amazing size all takes place in the cambium layer, just under the bark. Conifers (Pinophyta) are unlike many of our common garden plants, and for several reasons. The most obvious difference is that conifers are gymnosperms, which are cone-bearing seed plants.
Botanically, a cone is called a strobilus. Strobili protect the seeds as they develop. This can take from four months to three years, depending on the species and environmental conditions. Some species of conifer need fire to release their seeds. These cones, in particular, will stay tightly closed for 60 to 80 years, waiting for fire.
Cones can range in size from 1/10 of an inch to two feet in length. There are male cones that produce pollen, and female cones, where pollination occurs. Both types of cones are usually found on each tree. Different species of conifer spread their reproductive cycle out over one, two, or three years.
While some plant families include thousands of species, the conifers boast only 7 or 8 subfamilies (depending on which botanist you ask) and most of us recognize even fewer. There are less than 630 living species of conifer worldwide. These include pine, cedar, redwood, larch, cypress, fir, Douglas-fir, kauri, juniper, hemlock, yew, and spruce. All conifers are in the Pinales order and the Pinaceae family. Botanists break down the subfamilies in this way:
Abietoideae - fir
Cedrus - cedars
Cupressaceae - cypress
Larix - larch
Pseudotsuga - Douglas-fir
Tsuga - hemlock [Not to be confused with poison hemlock]
Piniodeae - pine
Piceoideae - spruce
Taxaceae - yew
Other subfamilies include Araucariaceae and Podocarpaceae, both found in the southern hemisphere, Sciadopityaceae, found in Japan, and Cephalotaxaceae, mostly found in SE Asia.
While there are fewer types of conifers, these trees once covered major portions of North America and they are still the world’s greatest carbon sink. Many conifers are grown commercially for softwood lumber, paper production, and Christmas trees. Stone pines are also grown for their delicious edible pine nuts.
Conifers hold nearly all the records for height (nearly 380 feet tall), girth (over 37 feet across), volume (over 1,400 square feet), and age (4,700 years). While each conifer species is unique, they also share many common characteristics:
Pruning pines is different from pruning other trees and plants. Where most plants will sprout at the bud nearest a cut, pines only have one growing tip per branch. If this growing point is cut off, the branch will die. Pruning conifers is done before the branches actually form. As newly expanding buds, or candles, are seen, they can be allowed to grow, or they can be pinched back. Candles can be pinched back partially or completely. Candles are where the needles emerge. The bud is pinched back just as the needles begin to emerge. Where you pinch will dictate where new growth buds will form.
Looking closely at the needles of a conifer is one of the easiest ways of telling the different species apart. If the needles occur in bunches of two, three, or five, it is most likely a pine. If the needles occur singly, it is probably either a spruce or a fir. If that single needle rolls easily between the palms of your hand, it is spruce. [It actually has four sides, but you probably won’t be able to tell.] If the needle feels flat and does not roll easily, it is a fir.
Conifer pests and diseases
Bark beetles and their larva (roundhead borers) can cause significant damage to members of the pine family. Adelgids, aphids, spider mites, spittlebugs, conifer twig weevils, nematodes, and sawflies can also cause problems. The larva of several moths, including the clearwing, rusty tussock, Douglas fir tussock, spruce budworms, and the Douglas fir pitch moth all feed on conifers. These evergreens are all susceptible to canker diseases, root rot, crown rot, slime flux, and needle casts. Some of these pests can be captured with sticky barriers.
The biggest problems faced by homeowners with conifers are wind, heavy rain, and flooding. Like many other trees, conifers have a shallow root system that spreads out very close to the soil surface. Because these trees carry so much weight above ground, they can tip over. This makes it very important to install potentially large trees far enough away from structures, such as your home, chicken coop, or garage, to prevent serious harm in the case a tree falls.
Did you get a conifer during the last holiday season? If so, check out my handy holiday plant care page!
Few weeds come up as quickly and resiliently as common groundsel.
Also known as old-man-in-the-spring, this European annual weed prefers our cool, wet winter weather, dying off each summer, but it never fails to return each year. In fact, common groundsel is classified as a ruderal species, which means it is one of the first plants to start growing in disturbed soil.
Common groundsel description
Like other members of the sunflower family, common groundsel (Senecio vulgaris) features a sunny yellow flower. Akin to dandelion’s, mature seed heads transform into puffballs that fly on every breeze. The flowers of common groundsel are smaller than those of dandelions, and the green bracts have black tips. The plant has an upright growth, reaching up to 2 feet in height, but usually closer to 16 inches.
Rather than the lion’s tooth leaves seen on dandelion plants, common groundsel features pinnately lobed leaves (with matching loops and curves on either side), and may be toothed near the edges. Leaves are smaller near the top of the plant and may be covered with fine hairs. The leaves are sessile, which means they attach directly to the plant. The stems are hollow and the root system is a shallow taproot.
If robbing nearby garden plants of sunlight and nutrients weren’t bad enough, common groundsel is also a carrier of disease pathogens (vector). It can host Cineraria leaf rust (Coleosporium tussilaginis), a fungal disease. It can also carry the fungus that causes black rot, another fungal disease that can affect citrus, chickpeas, cucurbits, such as cucumber or melon, tomatoes, and peas.
A toxic weed
While hailed as a medicinal plant, common groundsel contains chemicals, called pyrrolizidine alkaloids, that can make people and animals ill. Chronic exposure can cause irreparable liver damage. You’d have to eat an awful lot of it, but I avoid feeding it to my chickens, just to be on the safe side.
Controlling common groundsel
Common groundsel is self-pollinating. Each plant can produce 1,700 seeds, and there can be three generations per year. That ends up being a lot of weeds! The best way to control common groundsel is to prevent it from spreading in the first place. This means snatching seed heads any time they are seen and tossing them in the trash. Seedlings are far easier to pull than mature plants, so learn to recognize them and pull them out every time they are seen.
Heavy common groundsel infestations can be slowed or halted with sheet mulching. Follow these steps to successfully sheet mulch an area:
As with all weeds, this is an ongoing battle. Because these plants carry disease, it is better to be vigilant.
Bright, cheery colors, delicate textures, and you can eat them!
Edible flowers have been part of the human diet since, well, since there have been people! Did you know that carnation petals have been used as one of the ingredients in the French liqueur, Chartreuse, since the 17th century?
Before we start, let me first share a story from my early trials with edible flowers. My dear sister decided to marry an Australian sailor and asked me to make her wedding cake. It was a lovely tiered white cake with yellow borders. I decided to add some stunning yellow flowers I saw outside. My sister’s reaction of horror was not what I expected - until she explained that the Angel’s Trumpet flowers I used were extremely poisonous. Needless to say, the flowers and the frosting came off. So…
When in doubt, don’t
Before you go popping random blossoms in your mouth, you need to know that some flowers can make you sick, and others can kill you. If you are even remotely unsure about a plant, do not eat it. Sometimes there is a fine line between edible and inedible. For example, regular garden variety pea flowers and shoots are edible and delicious, while fragrant sweet peas (Lathyrus odoratus) are poisonous. Some varieties of daylilies are edible and others are not. The same is true for phlox and geraniums. Make sure you know what you have before tasting it.
Also, chemical sprays and car fume residue can be toxic, too. Chemical pesticides, herbicides, and insecticides should not be used on flowers that will be eaten. Never eat flowers from commercially grown plants, as there is no way to know for sure what has been applied to or used in growing these plants. Now that I have reminded you to be careful, let’s see just how many flowers in your garden are edible!
All herb flowers are edible.
Basil, chives, cilantro, garlic, dill, lavender, marjoram, mint, oregano, rosemary, sage, savory, and thyme flowers can all be used to add an extra depth and a touch of color to many different dishes. You can also eat the flowers of anise hyssop, angelica, bee balm, burnet, chervil, fennel, ginger, and lemon verbena.
There are a surprising number of edible flowers. All members of the viola family, which includes Johnny-jump-ups and pansies, and the dianthus family, or carnation fame, are edible.
Edible fruit tree flowers
The flowers of many fruit and nut trees are also edible. Apple, apricot, peach, pear, and plum blossoms can be used to add color and a delicate complexity to many dishes. When using these flowers, be sure to only use the petals, and not the stamens or pistils. Because they contain low levels of cyanide, apple blossoms should be eaten in moderation. Citrus blossoms are very pungent and should be used sparingly. Leftovers can be added to floral arrangements, so that you can still enjoy the aroma.
Edible vegetable flowers
Your probably already eat several vegetable flowers: artichoke, broccoli, and cauliflower, for example. While eating the flowers of your vegetable plants reduces your crop yield, it can be a nice way to try something new. There are several different vegetable plants with edible flowers:
Ways to use edible flowers
While it is easy to sprinkle petals into a salad for a splash of color and flavor, there are many other ways to incorporate edible flowers into your diet:
Preparing edible flowers
Edible flowers should be picked just before using and thoroughly rinsed off. This will help remove dust, frass, microorganisms, and any surface chemicals that may have blown in or been applied. Taste the flowers before using them, so that you know what flavor you are adding to your food.
Remove the pistils and stamens from most flowers. The only exceptions are violas and Johnny-jump-ups - in these cases, the other parts add good flavor. If you detect some bitterness in any edible flower, you may need to remove the white base of the petals. This is commonly needed when working with carnations, chrysanthemums, day lilies, and roses.
How many edible flowers do you have in your garden? Tell us in the comments!
Have your new seedlings been chewed off at ground level? It may be darkling beetles.
Darkling beetle is the common name for all 20,000 species within the Tenebrionidae family. Some of the more famous California darklings include Blapstinus, Coelus., and Eleodes..
Darkling beetle identification
Darkling beetles are dull black, blueish-black, or rusty brown, depending on the species. Unlike other beetles, the wings of darkling beetles are fused together. Some species have longitudinal ridges on their wing covers, but most are smooth, without markings of any kind. One exception is the wooly darkling beetle (Eleodes osculans), which is covered with tiny hairs. Darkling beetles can range from 1/8 to 1-1/2 of an inch long. The antennae are well developed and often have knobs at the ends (clubbed).
Darkling beetles are frequently confused with predaceous ground beetles (Carabidae), but ground beetles are shiny and their antennae are more delicate. There are other differences, but you get the idea. Darkling beetle larva look like pale yellow or dark brown wireworms. They are less than 1/3 of an inch long and are often called false wireworms. You may know one particular branch of this family as mealworms (Tenebrio molitor).
Did you know that mealworms can digest styrofoam?
Stanford researcher Craig Criddle discovered that the bacteria found in a mealworm’s gut can transform polystyrene into “carbon dioxide and recyclable organic waste.” How cool is that?!!? (UCANR)
Darkling beetle behavior
These pests tend to walk with their heads down and their abdomens somewhat lifted. Very often, they will stand completely still, in a headstand position, if frightened. While not dangerous, they can squirt you with a nasty smelling secretion from that rear end that does not wash off easily. This behavior is what gives some darkling beetles the name Skunk Beetle or Stink Beetle, not to be mistaken with stinkbugs. For the most part, these pests only come out at night, but you may catch one running across the patio or lawn during daylight hours. Normally, they hide under dirt clods, fallen tree bark, rocks, boards, wood chips, and in other dark places during the day. Often, the only way you know you have a darkling beetle problem is because of the damage they cause.
Darkling beetle damage
In addition to attacking seedlings at ground level, darkling beetles feed on the foliage of many garden plants, such as lettuce, chicory, cabbage, broccoli, and other brassicas, beans, melons, pumpkins, tomatoes, and squash. This feeding can be seen along leaf edges and on the underside of leaves. Darkling beetles also feed on the ‘netting’ (raised areas) of melons, the flowers of most cucurbits and pistachio, and on some fruit crops, such as figs.
Some species of darkling beetle also act as vectors for plant diseases and poultry parasites. Some darklings can also cause structural damage to insulation and wooden buildings. They are also attracted to poultry feed, but my guess is that the chickens make short work of that arrangement, as long as the unavailable feed is stored properly, in a metal container.
Darkling beetle control
Commercial farmers use insecticides to kill these pests. They also use a shallow ditch, filled with water, to block these pests from coming out of the weeds and into the fields. If you are an organic grower, as I am, you will have to use cultural controls. You can minimize darkling beetle damage organically when you:
In 2015, a report published by The Coleopterists Bulletin warned that three non-native darkling beetles have been found in California and Nevada. Each of these species is somehow tied to ant or fire ant populations:
I was unable to find any freely available photos, so you will have to track them down on your own. If you see any of these invasive beetles, please capture them and contact your local County Extension Office.
You may be surprised to learn that some people keep darkling beetles as pets.
Allelopathy is the scientific word for chemical warfare in the plant world.
There is plenty of New Age talk about ‘companion plants helping’ each other, but that is not true. Plants do not choose to help their neighbors. [We’ll get into the discussion about ‘plant intelligence' another day.] The truth is, life is a battle. Even in the garden.
Competition for resources
Most plant roots are constantly competing with neighboring plants for water and mineral nutrients. In the same way, most plants reach for as much sunlight as they can get, regardless of the needs of neighboring plants. That’s life. Its not a decision; its survival. Weeds compete with your garden plants by growing faster. Some plants use tendrils to climb other plants. And some plants use chemicals against neighboring plants and other organisms.
What is allelopathy?
Allelopathy [al-el-ah-path-ee] is a common way for plants to reduce competition in the immediate vicinity, and to reduce feeding by herbivores. Allelopathic plants actively discharge chemicals through their leaves, bark, and roots, as they decompose, and through other processes. These chemicals can stimulate or inhibit the germination, growth, development, reproduction, and survival of other plants and organisms. Autotoxicity is the flip side of allelopathy. In autotoxicity, plants generate chemicals to inhibit the growth of the same species in the vicinity. The chemicals used in allelopathy always impact other species of plants and organisms. These biochemicals are called allelochemicals.
Allelochemicals can interfere with another plant’s nutrient uptake, photosynthesis, pollen or seed germination, cell division, and even specific enzyme functions. These battles are being fought on the cellular and molecular levels! Because of these effects, allelochemicals are used in commercial agriculture as natural herbicides. For example, the lemon bottlebrush plant (Callistemon citrinus) produces an allelochemical called Leptospermone. Leptospermone is not strong enough on its own to be effective, but a synthetic version, nestorione, is. Nestorione is commonly used to control broadleaf weeds in corn, as well as the crabgrass in your lawn. Allelochemicals are also used as growth regulators, insecticides, and antimicrobial products. One advantage to using allelochemicals is that they tend to not have long term residual effects. Caffeine, and certain flavonoids, tannins, and phenols are all allelopathic chemicals.
Plants grow where their resource needs can be met. Because of this, allelopathy is an important player in species distribution and population density in the world and in your garden. In some cases, allelopathy gives weeds and invasive plants the upper hand. Nutsedge, garlic mustard (Alliaria petiolata), and spotted knapweed (Centaurea maculosa) all use allelopathy to beat out the competition. The allelochemicals used by garlic mustard have been shown to interfere with native tree roots and their mycorrhizal fungi, which help the trees gather mineral nutrients from the soil.
Allelopathy and incompatibility
Since some plants leave behind an allelopathic residue, it is a good idea to be aware of the potential for incompatibility when intercropping (succession planting), mulching, using green manure, planting catch crops, or when rotating crops. For example, decomposing straw has been shown to suppress weed growth, as well as reduce the number of pests and diseases found in an area, because of the allelochemicals contained in the straw. As it decomposes, it also improves soil structure and soil fertility. At the same time, decomposing straw temporarily increases the carbon-to-nitrogen ratio, so you may need to supplement the area with nitrogen.
Catch crops, planted to protect the soil from erosion between major crops, are an excellent way to protect your soil, but they also introduce allelochemicals that may interfere with the next crop. One sorghum-sudangrass hybrid (Sudex), in particular, can kill 50 to 75% mortality of your tomato, broccoli, and lettuce plants!
Many common plants use allelochemicals. Black walnut is the most notorious, but the story isn’t (as is often the case) as simple as it is made out to be. Black walnut (Juglans nigra) produces several allelochemicals which are said to block everything from growing underneath. This is simply untrue. The chemicals involved, and the interactions, are far more complex than that. Onions, beets, squash, melons, carrots, parsnips, beans, yarrow, stonecrops, and corn can all be grown near a black walnut tree without any problems, according to the PennState Extension. At the same time, blackberries, raspberries, blueberries, asparagus, eggplant, peppers, potatoes, and tomatoes do not grow as well when planted near a black walnut tree, according to the University of Illinois Extension.
Allelopathy and agriculture
Most of the research regarding allelopathy focuses on commercial agriculture. It tells us that rice, some Eucalyptus species, and the Tree of heaven (Ailanthus altissima) all use allelochemicals. It also demonstrates that rye mulch significantly reduces broadleaf weed growth, and that growing mung beans in a corn field reduces crop yield, while growing tobacco in the same corn field increases corn production.
Allelopathy in the garden
This is a highly complex issue that cannot be watered down very far before everyone is simply guessing. That being said, I have been able to glean the following useful information for the home gardener:
If you suspect that two plants are incompatible, simply conduct an online search, using both plant names and the word allelopathy. If there is any research available, please let us know in the comments section!
Most of the ‘rules’ associated with allelopathy have been developed with large-scale agriculture in mind. They are diluted by all the other factors occurring in your garden and compost pile, so take it with a grain of salt.
This information is not going to stop me from composting my healthy pea plants, but it will make me more aware of my plant choices, when it comes to cover crops, crop rotation, and catch crop planting.
Ratta-tat-tat-tat-tat-tat. That rapid-fire drilling can only mean one thing: woodpeckers.
What are these birds looking for and can they damage your trees? Let’s find out!
What a headache!
The familiar drumming sound of a woodpecker hammering on a tree (or your house!) can mean they are looking for food, or a mate. They may also be excavating a nesting site. When a woodpecker drums on a tree trunk, or the side of your house, they do so at a rate of 20 to 25 times per second, with a force of 1200 grams. On average, a woodpecker weighs 100 grams. So, imagine banging your head on a wall, 20 times a second, with a force equal to 12 times your body weight! Woodpeckers perform this behavior on a daily basis without knocking themselves out, or causing brain damage. That’s pretty amazing. So amazing, in fact, that woodpeckers are studied extensively for things like shock-absorbers. It ends up that a woodpecker’s head can withstand a deceleration of 600 to 1500 grams, while the human brain can only handle 300. So, let’s see what all that drumming and drilling is about.
Both genders drill holes in wood to reach burrowing insects (pests) and to stimulate the flow of sap from the cambium layer. Woodpeckers eat the sap, and they use it to attract and trap insects, which they also eat. Anna’s hummingbirds and ruby-crowned kinglets also take advantage of this buffet created by woodpeckers. [They sure as heck can’t drill those holes for themselves!]. Woodpeckers also eat fruit, nuts, and berries, but they are, generally, not a significant problem in this way.
Male woodpeckers use the drilling to demonstrate their prowess to local females and to claim territory. The better the resonance, the better the performance, which is why many homes are chosen over nearby trees. They will even use metal rain gutters and downspouts during the peak of the breeding season. Females also enjoy drumming, both for food and to alert males to their presence.
Classically, woodpeckers are black and white, and males feature some red, usually on the head. The beak is sturdy and sharply pointed. You may not ever see it, but woodpeckers have a very long tongue, which they use to pull larva and other insects out of crevices. If you look closely, most woodpeckers also feature short legs and two, backward-facing toes with sharp claws. These 'zygodactyl' toes, combined with a stiff tail, help hold the bird in position while drilling.
The name ‘woodpecker’ actually refers to woodpeckers, sapsuckers, and flickers. These birds are all in the same family (Picidae). California is home to eleven woodpecker species, four sapsuckers, and two flicker:.
Acorn woodpeckers are particularly destructive to homes because they wedge acorns into all the holes they create. A single acorn woodpecker may collect and store thousands of acorns between wooden shakes and shingles in a single season!
Sapsuckers are a shy group. If you walk by, they will scuttle to the other side of a tree trunk, trying to stay hidden. These birds make a mewing sound. They drill rows of round or squarish holes in certain trees. All sapsuckers have a white rump, white wing patches, and there is always a degree of yellow on the belly. There are four different sapsuckers here in California:
These once common birds are losing ground to introduced starlings, which aggressively compete for nesting sites. Flickers love to eat ants and na be seen hopping up and down tree trunks in search of these treats. There are two species of flickers in California:
Preventing woodpecker damage
The problem with woodpecker feeding is that the loss of sap may weaken a tree, and it creates a point of entry for other pests and pathogens. Unless the feeding is extensive, however, most trees can handle it without much of a problem. If the feeding becomes a problem, woodpeckers can be blocked by panels of lightweight sheet metal or 1/4-inch hardware cloth wrapped around the favored feeding areas.
Woodpecker drilling can also cause structural damage to your home. This is especially true for trim boards, eaves, and wooden siding. Woodpeckers seem to prefer redwood and cedar. They are also attracted to plywood and other layered arrangements that create tiny spaces perfect for tasty insects.
All woodpeckers are protected under the Migratory Bird Treaty Act of 1918. But, you can use exclusionary measures to protect your home. The most effective method is to tightly stretch 3/4-inch bird netting over the eaves of your home, or to cover the side of a favored feeding/drumming wall.
Research has shown that repellents and frightening devices are not effective. Urban myth claims that hanging nesting boxes and providing suet is one way to eliminate the risk of woodpecker damage. Research has shown that these provisions do not consistently reduce the problem and may actually attract even more woodpeckers into an area.
Benefits of woodpeckers
Before we try to ban these beautiful birds from our gardens, keep in mind that the nesting holes they create are often used by other native, cavity-nesting birds. Woodpeckers also remove a significant number of potentially damaging insects from our fruit and nut trees. Finally, we do not yet fully understand the value of biodiversity.
While not a native of California, this magnificent bird of the Mississippi Delta deserves mention. The Ivory-billed woodpecker (Campephilus principalis) was/is believed to be extinct. The last confirmed sighting occurred in 1944. In 2005, video emerged that may have been of an Ivory-billed specimen. There is some debate about this, as it could also have been a slightly smaller, common Pileated woodpecker. The Cuban ivory-billed woodpecker has been considered extinct since 1987. Ivory-billed woodpeckers are/were very large. At 20” long, with a 30” wingspan, they must have been hard to miss. They were able to live 20 to 30 years, but Native Americans decided that the Ivory-billed woodpecker’s massive bone beak was a prized decoration, so the killing began. If you are ever lucky enough to hear the tell-tale double-knock of an Ivory-billed woodpecker, record it, photograph it, and contact the Audubon Society right away!
Did you know that a group of woodpeckers can be called a ‘gatling’ or a ‘drumming’ or a ‘descent’?
I didn’t either.
Do you have any woodpeckers visiting your garden? Tell us which ones in the comments!
You can grow a surprising amount of food in your own yard. Ask me how!
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