Garden Word of the Day
Take $5 off planting calendars from Forging Time with the code DAILYGARDEN841. This is an excellent resource with some amazing photos.
Ramularia Leaf Spot
What do artichokes, barley, beets, patience dock, rhubarb, and strawberries have in common?
Besides being delicious, they are all susceptible to a fungal disease called Ramularia leaf spot (RLS). Cotton, daffodils, jonquils, and narcissus are also vulnerable, along with several other wild plants, such as cowslip.
Ramularia leaf spot symptoms
Like most other leaf spot diseases, this one is characterized by, you guessed it, leaf spots. Reddish-brown spots occur on both upper and lower leaf surfaces. Those lesions often have a yellow halo but can be angular, circular, or rectangular, making this disease difficult to identify. Some even call Ramularia the master of disguise. To get a clear identification, growers refer to the 5R’s of Ramularia infection:
Brown ulcers may also occur on flower bracts. Eventually, those bracts will curl up and dry out. Growers believe this disease is spreading rapidly because it is difficult to identify with certainty, but you can always assume that spots warrant a closer look.
In the case of Ramularia leaf spot, entire leaves will eventually shrivel up and die, taking millions of white fungal spores with them. Then those spores are splashed onto neighboring plants through rain and overhead watering.
Ramularia leaf spot lifecycle
Ramularia fungi have a rather complicated life cycle, and there are several varieties with slightly different symptoms, but let's keep it simple, shall we? Most importantly, this disease spreads through infected plant debris and seeds, and on the wind. Once spores come into contact with a plant, lesions form on lower leaves, spreading to upper leaves, then flowers. Those flowers produce infected seeds that continue the cycle.
Ramularia leaf spot management
Infected commercial crops are sprayed with fungicides up to eight times a year with limited success. Of course, you need to wear protective clothing and limit the number of hours you spend around these chemicals, so you might want to think twice before applying them to your groceries.
Since stressed plants are more likely to become infected, keeping your plants healthy with these tips can prevent many problems:
Figuring out what leaf spots are telling you can be tricky, but it's worth the effort to find out.
Do you see flecks of bleached or straw-colored areas on the leaves of your strawberries, summer squashes, or corn? Or flecks and bands of red, orange, yellow, or brown on conifer needles? Those discolorations are caused by ozone, and the damage is called weather fleck.
Technically, it is weather fleck only when it affects tobacco plants, but for the sake of this discussion, we’ll use the term more broadly.
So what does ozone do?
Ozone (O3) creates a barrier around the Earth, up in our stratosphere, protecting us from the sun’s harmful ultraviolet radiation. As a type of air pollution, it can also cause cardiovascular, central nervous system, respiratory, and reproductive problems for us.
Excessive ozone can also reduce chlorophyll, carotenoid, and carbohydrate levels in plants while increasing ethylene gas levels. Ethylene is responsible for ripening, but excessive levels are considered air pollution.
Ozone triggers plants to protect themselves, reducing fruit yield and quality. In 2022, a study found that East Asia lost $63 billion in crops due to ozone pollution in one year. Ozone forms as sunlight reacts with car and factory fumes, so there’s plenty of it. It is considered the most destructive air pollutant for plants in the United States. Nearly all plants in urban areas are affected to one degree or another. Ozone is a reactive form of oxygen that can cause many symptoms in broad-leaved plants.
Symptoms of weather fleck
Bleaching, bronzing, chlorosis, mottling, stippling, tissue death, and weather fleck are common symptoms of ozone damage. Weather fleck starts as small, dark green water-soaked areas. Within hours, those lesions turn brown, then tan or white. At higher ozone concentrations, this process can occur in just two or three hours.
You might mistake weather fleck for spider mite feeding, except that symptoms are usually seen on the upper surface of mature leaves first, followed by younger and older leaves. Spider mites almost always start on the underside of leaves, trying to stay hidden.
As ozone exposure continues, damage spreads to both sides of the leaves. Mature plants are more resistant to ozone than younger plants, but those damaged areas are dead tissue. Weather fleck doesn’t look very impressive, but those tiny damaged areas can merge and form bigger problems.
Any time tissue is damaged, it becomes less able to protect itself. Plants exhibiting weather fleck are especially susceptible to Botrytis fungi. Botrytis is responsible for grey mold. These plants are also experiencing internal stresses that cause cell seepage, chemical imbalances, and other problems.
The list of plants highly susceptible to ozone damage is rather long:
Many garden ornamentals, such as dahlia, fuchsia, lilac, marigold, and salvia are also very sensitive to ozone levels.
If you live in an area with lots of ozone, you may want to focus your gardening efforts on somewhat resistant cucumbers and peppers. What else can you do?
Aside from working from home and walking to the store instead of driving, you can protect your plants by not giving them more fertilizer than necessary. Plants are most susceptible to ozone damage during periods of rapid growth.
Did you know that ozone smells a little like chlorine? I didn’t, either.
A well-lit garden path can be a pleasant experience on a summer evening, but what do those lights do to your plants? Let’s find out.
Light at night is not natural. Nothing, us included, evolved to deal with artificial light at night. And we are all light-sensitive to one degree or another. Chickens produce more eggs in summer when their chicks have the best odds of survival. So chicken farmers put their hens under lights to get as many eggs as possible, as quickly as they can. This arrangement works well for the farmers. But it is hard on the hens. Left to live a natural life, the average hen can live 10 to 20 years. Commercial hens generally live only 3 to 4 years. All of those lights and productive demands are hard on people and plants, as well.
Sources of night light
There are many sources of artificial light at night. Street lights, porch lights, decorative path lighting, and security lighting are the most common sources of light at night. Depending on where you live, headlights, factory lights, and strip mall lighting may also be sources of artificial light for your plants. And indoor plants are subject to our overhead lights, reading lamps, and computer and television screens. It’s a wonder anything gets any sleep these days!
The natural cycle of light and dark triggers circadian rhythms within us that allow us to sleep, repair ourselves, and recover from the demands of our days. Plants have similar needs. While plants use sunlight to perform photosynthesis during the day, they need darkness to produce an important compound called phytochrome.
What is phytochrome?
Phytochrome regulates several functions within plants, including abscission, dormancy, photoperiodism, and seed germination. Without healthy seed germination, our gardens might be rather dismal places. And photoperiodism allows plants to anticipate the seasons, triggering them to bloom, grow, and rest at the proper time of year. That is where ‘short day’ and ‘long day’ varieties come in. They use photoperiodism to tell them if the correct balance of daylight and darkness hours is right for them to bloom and grow safely.
Plants are much more sensitive to the number of daylight hours than you might expect. For some plants, as little as one-minute exposure to a 25-watt bulb is enough to halt blooming. Strawberries are very light-sensitive. If they don’t receive enough darkness, you might not receive any berries.
The number of hours of daylight can also cause bolting, which can shorten the useful life of your lettuces and spinach. If bolting is a problem in your garden, you may want to turn off some of those lights.
Abscission and dormancy
As the days get shorter and the nights get longer, plants produce hormones used to protect themselves through the colder winter months. Those phytohormones tell plants to pull nutrients out of leaves and let them fall. If any part of that natural cycle is interrupted or interfered with, plants can be unprepared for winter weather, making them more susceptible to pests and diseases.
Night lights and insects
We all know that moths are often attracted to porch lights, but nighttime lighting attracts several other insects to our landscapes. Research from the University of Exeter has shown that night lights “trigger complex effects on natural food webs [and that they] may have more permanent, widespread impacts on wildlife and ecosystems.”
Managing light pollution
Now we know: too much light at night can adversely affect our plants. So it’s up to us to reduce light pollution (and air pollution) to improve the health of our plants and the food they produce for us. Try some of these tips to help reduce light pollution in your home and landscape:
With a good night’s rest, you and your plants will both feel better.
When someone starts talking about xeriscapes most of us picture gravel and succulents. There might be a yucca plant and some big rocks, but none of that sounds very appetizing to me. So I decided to see which edible plants could be part of a xeriscape. Here’s what I found out.
What are xeriscapes?
Xeriscapes are low-maintenance landscape designs that use little or no water. Designed to reduce evaporation and runoff, they cut pollution. Xeriscapes incorporate plants best suited to the local climate. These plants have evolved to thrive without the addition of water, fertilizer, herbicides, or pesticides, hence the reduced pollution. The goal of a xeriscape is to conserve water, but they save time, too. How much extra time would you have if you didn’t need to water your garden? The only help an established xeriscape needs is occasional weeding and mulching.
These gardens also tend to promote biodiversity, but water is the key. In arid regions, such as Arizona and Nevada, as much as 75% of household water is used to water lawns. You may be surprised to learn, as I was, that xeriscapes containing trees reduced the heat island effect by nearly 5°F. Imagine how that temperature change could help save on your electric bill! But what about edible plants?
Planning your edible xeriscape
Most edible plants need far more water than would be used in a xeriscape, but not all. To start your xeriscape design, create a drawing to scale of your property. You can find a trick to doing this in my post on sun maps. Once you know where everything is, you can start your xeriscape plan:
Once plants are in place, add 2 to 4 inches of mulch around, but not touching, your plants. If you opt for stone or gravel mulch, know that it will reflect sunlight into the underside of the plants, creating more heat.
Edible plants for your xeriscape
While these plants will all need some irrigation, especially as they are getting established, they should be able to provide you with edible crops using far less water than other traditional garden crops. Also known as dryland farming, this method uses plants that have evolved to use water stored in the soil from the previous winter’s rainfall. Some of these offer the convenience and ease of being perennial, too!
Many of these plants will produce smaller-than-normal fruits when grown in a xeriscape, but the reduced water content translates into intense flavor and more sugar. You can see my post on deficit irrigation to learn more about that. Some people also grow corn, pumpkins, and even tomatoes in their xeriscape, though I’m not sure how well that would work.
Herbs are your blue-ribbon xeriscape plants. Most of them evolved in poor, rocky soil. The aromas and flavors we love them for are defense mechanisms against insect and herbivore feeding.
Caring for your xeriscape
The trick to watering a xeriscape is to do it deeply and infrequently. As plants become established, they will need little or no irrigation. Water in the pre-dawn hours or evening by laying a hose on the ground near plants that need watering to reduce evaporation. As always, groups plants by their light and water needs. And be sure to add a fallow period to your crop rotation so that you don’t deplete the groundwater or nutrients.
It may surprise you, but rain gardens are a type of xeriscape.
Do you know any other edible plants that would grow in a xeriscape?
Let us know in the comments!
Tomato sauce and bouquet garni wouldn’t be the same without bay leaves. But can we grow bay at home? Let’s find out.
Bay leaves come from the bay laurel tree. Also known as sweet bay, true laurel, and Grecian laurel, these trees are not to be confused with California bay laurel or cherry laurel. We’ll learn more about them in a minute.
Bay laurels (Laurus nobilis) are evergreen shrubs or small trees native to the Mediterranean basin. Bay forests once covered that region. As humidity levels dropped and temperatures rose, the laurel forests retreated, and more drought-tolerant species moved in.
Uses for bay laurel
Bay leaves flavor more than your favorite spaghetti sauce. Bay leaves can add flavor to stocks, stews, and other savory dishes. Dried bay laurel berries are also spices, and burning the wood creates a unique smoke flavoring. But that’s not all.
In ancient times, high-status bay laurel wreaths donned the heads of Olympic athletes and political leaders. Laurel oil was said to treat bruises, ear aches, paralysis, rheumatism, and sciatica, but I think they took things a bit far. More recently, bay leaves have been applied as an astringent to treat small wounds. The oil is popular in massage and aroma therapies. It is an ingredient in Aleppo soap. The fragrance certainly is relaxing.
Bay laurel description
Many of us are familiar with smooth, lance-shaped bay leaves. They are shiny and dark green while fresh. Trees can grow more than 50 feet tall, but most people keep theirs pruned to heights of two to eight feet. These plants produce small, yellowish-green flowers. The fruit of bay laurel is a small, shiny purplish-black drupe
How to grow bay laurel
Bay laurel plants can be grown from seed or cuttings. The easiest way is to buy a bare-root tree. These trees are dioecious, so some are male, and some are female. Since we mostly grow them for their leaves, this isn’t a problem. If you want berries, however, you’ll need one of each to get a crop.
These shrubs lend themselves very well to the home garden in USDA Hardiness Zones 8 through 10. You can also grow them as containerized indoor plants. A 5-gallon pot is big enough. Bay laurel prefers full sun to light shade. If grown indoors, it will need lots of bright direct sunlight.
Bay laurel prefers slightly acidic soil with good drainage. These trees benefit from wind protection, so select a site with that in mind. You can use bay laurel as a topiary, shaping and twisting it to your heart’s delight.
Bay pests and diseases
Bay laurel trees protect themselves against most pests and diseases. Soft scale (Coccus hesperidum) and jumping plant lice (Trioza alacris) are two insect exceptions. Phytophthora root rot and leaf spot and shot hole disease make also occur.
Yellowing leaves on bay laurel often mean they need more nitrogen. A lab-based soil test is a good idea.
And what about those other laurels? It is not safe to assume they are all the same. Some of them are poisonous. And others can be a real headache.
Here's a summary of those other laurels:
So, you can grow an edible bay laurel tree at home. It makes a lovely houseplant and a great addition to your dinner menu.
Tree roots may surprise you.
We used to think trees looked pretty much the same underground as they did aboveground. We once thought trees sent taproots deep into the earth to suck up water and nutrients and hold themselves upright. All of those things are true except for the first one. Now we know that most tree roots extend laterally far more than horizontally. Most tree root systems extend 4 to 7 times the diameter of the aboveground portion. The root system of a mature oak can extend up to 250 feet! We also know that they communicate and exchange nutrients with neighboring trees, but that's another discussion. Today, our garden topic is root plates.
What are root plates?
Root plates are the combined disk-shaped mass of roots and soil immediately surrounding the trunk of a tree. If you have ever seen a tree knocked over by a strong wind, you have probably seen a root plate.
These structural roots and soil form massive disks. As tree roots spread out just under the soil surface in search of water and nutrients (and possibly neighbors), they quickly taper as they grow away from the main stem. The root plate edge occurs where the roots shift from thick and stiff to somewhat thinner and more flexible.
Generally speaking, you can assume that for every inch of trunk diameter at chest height, these critical roots extend one foot in every direction. Smaller transport roots emerge from these structural roots to carry the food and water collected by fanning absorbing roots. These secondary roots help delay the symptoms of damage to the root plate. But they can’t carry the extra burden indefinitely.
Trees store approximately 2/3 of the energy they create in their root systems. If those roots are severed or damaged, those stored nutrients are lost. Eventually, there is a deficit. Symptoms of a damaged root plate may take three to seven years before symptoms appear. By then, it may be too late.
Nearly all tree roots are in the top 18 to 36 inches of soil. The combined mass of root material and soil is called a root plate. Because most tree roots are shallower than we thought, we now know that tree roots are more susceptible to our actions than we thought. But there are benefits.
The benefits of wide, shallow rooting
Trees with shallow roots spreading out in all directions have better access to the nutrients in decomposing leaf litter and other plant debris. They are also close enough to the surface for critical gas exchanges. Trees need nutrients, oxygen, and water to grow. Deep soil does not contain enough water or oxygen for trees to thrive, so they look elsewhere.
The downside of root plates
Shallow-rooted trees are more likely to fall over. A strong gust of wind can tear the root plate free from smaller roots. The entire disk of roots and soil can slip, spin, and upend a tree. We’re talking about massive force when trees break loose. And root plates are equally impressive. For example, a root plate that measures 11-feet across and 2.5 feet deep would have an average volume of more than 270 cubic feet and weigh more than 14 tons. You don't want any of that falling near your home or car.
How can we help our trees?
So, what can we do to keep our trees from falling over?
Did you know that corn, sunflowers, and wheat have root plates? I didn't either.
Nutmeg and Mace
Eggnog, melon slices, and morning oatmeal are just a few things made better with nutmeg and you just might be able to grow your own.
If you live in USDA Hardiness Zones 10–11 or have a greenhouse, you can grow nutmeg. If you can’t grow your own, it’s still a fascinating plant.
Nutmeg tree description
The nutmeg tree (Myristica fragrans) is native to Asia and the western Pacific. It is an evergreen that can grow 50 feet tall or more. Leaves are dark green and can be two to six inches long. They look similar to magnolia leaves. Pale yellow, bell-shaped flowers grow in loose clusters.
Nutmeg tree flowers
Similar to avocado trees, nutmeg trees change their gender. Instead of altering flower gender within a single day, nutmeg trees mostly begin as male. As they get older, they may turn female. You’ll probably need more than one tree to get a crop unless you can find a self-pollinating variety.
Male flowers tend to have one to ten flowers on short stems, while female flowers grow in groups of one to three on slightly longer stems. In some cases, female flowers do not have petals. Nocturnal beetles are responsible for most nutmeg flowers pollination.
Nutmeg fruits can be oval or pear-shaped. They are two inches long, smooth, and yellow. As the fruit ripens, it splits in half, exposing a shiny red coating called the aril that creates a web around the seed. The aril from nutmeg trees is what we call mace. I was surprised to learn that nutmeg fruit is also edible, though I have read that it tastes nothing like the nutmeg spice.
How to grow nutmeg
You can grow nutmeg from seed or start with a seedling. If you get an untreated nutmeg fruit for growing, place it in a paper bag and put it in the refrigerator for up to 45 days. Stratification of the seed in cold triggers hormonal changes that help the plant grow properly. Soak the seed in water for 24 hours prior to planting. Then plant the seed one inch deep in loose, nutrient-rich soil. Keep the soil warm and moist. You should have a nutmeg sprout in six to eight weeks.
Nutmeg can be grown in a large container (10 gallons is ideal). If you put nutmeg trees in the ground and have more than one, space them 30 to 40 feet apart.
Nutmeg trees prefer hot, wet weather, neutral soil, and good drainage. You’ll need to keep the soil moist but not soggy. Dry soil and nutmeg trees don’t mix. Two inches of water each week is a good standard for these trees. And mulching around your nutmeg tree (but not touching the bark) will help retain moisture and stabilize temperatures.
Top dressing around your nutmeg tree with composted manure will provide many important nutrients. You can also use a standard fertilizer or fish emulsion.
Nutmeg trees grow best in dappled shade with four to six hours of direct sunlight and 77–86°F temperatures.
Nutmeg tree problems
Once established, nutmeg trees have few problems. Holes in seeds indicate cocoa weevils are present. Anthracnose leaf spot and thread blight are the two most common diseases. You can use a Bordeaux mixture or fixed copper to prevent both.
Many people have used nutmeg and mace from the grocery store, dried, ground, and bottled. Like many other edibles, homegrown or simply freshly grated, nutmeg and mace add new layers of taste and fragrance to your baking.
When I first saw star anise, I assumed it was a seed. I was wrong.
The brittle black stars that smell akin to licorice and bring a rich sweetness to many Chinese dishes and Vietnamese pho are the dried fruits or pericarps of an evergreen tree that you can grow at home.
Star anise (Illicium verum) gets its name from the Latin words for true seduction. If you’ve ever experienced the lush, potent fragrance of star anise, you know how well this name fits.
How is star anise used?
While star anise tastes similar to anise, they are not related. Star anise is the primary ingredient in five spice powder, with cinnamon, cloves, fennel, and Sichuan peppercorns. Added to baked goods, herbal teas, mulled wine, poached fruit, and savory dishes, star anise brings depth and complexity. And the plant is quite lovely.
The star anise plant
Star anise trees grow fast. They can reach a height of 26 feet with a 10-foot spread, but are often kept much smaller by pruning.
The leaves are lance-shaped and fragrant but not used in cooking, and the flowers are pink or dark red.
The fruit is star-shaped and green until it ripens. Ripe star anise fruit is brown and woody. Each of the spikes of a star anise fruit is a carpel that contains a single seed
How to grow star anise
These plants are native to southwest China and Vietnam and prefer warm temperatures and dappled sun (think lower in the jungle canopy). They can be grown outdoors year-round in USDA Hardiness Zones 7–9. If you live in a cooler region, give your star anise full sun and protect it from wind and frost. One way to do this is to grow it in a large, wheeled container. Simply bring it indoors each winter.
The easiest way to grow star anise is by buying a certified disease-free sapling from a nursery. But don’t confuse these delectable spices with Japanese anise (Illicium anisatum) or swamp star anise (I. parviflorum) because those plants are toxic. And remember to place your new tree into quarantine to prevent bringing new problems into your landscape.
If grown from seed, it will take six years before you get a crop. You can also grow star anise from a branch cutting. These trees prefer loamy, slightly acidic soil (pH 6.0–7.5) and constant moisture. Your star anise tree will grow best with one inch of water each week, allowing the soil to dry out between waterings.
Top dressings of aged manure or compost can ensure your star anise gets the proper nutrients in spring and summer. Do not feed your tree in autumn or winter.
You can also grow star anise as a hedge, but it will require regular pruning because of how quickly it grows. Pruning star anise generates amazing smells!
Unripe fruits are harvested and left to dry. They can be stored for years in an airtight container.
Problems associated with star anise
Because of the oils that make star anise so fragrant, insect pests are not a problem for this tree. Alternaria blight and downy mildew, however, can cause problems. Use neem oil or fixed copper to prevent these problems.
Did you know that star anise used to be used to make Tamiflu? I didn’t, either.
Palestriped Flea Beetles
Are you seeing small holes in the leaves of your garden plants? It may be palestriped flea beetles.
Palestriped flea beetles (Systena blanda) feed on artichokes, cabbages, and radishes. Beans, carrots, sunflowers, and other edibles are also at risk. Likely, you won’t even see these culprits unless you look closely.
Like other flea beetles, palestriped flea beetles are small insects with large legs for jumping. And they can fly. But they feed on the underside of leaves, so it’s easy to miss them until you start seeing those holes.
Palestriped flea beetle description
Unlike their close cousin, the striped flea beetle (Phyllotreta striolata), and somewhat contrary to their name, palestriped flea beetles have a distinct white band down each wing. Striped flea beetles have wavy gold markings. Both species are only 1/8 of an inch long and tend to be brown with relatively long antennae.
Eggs are elliptical and pale yellow, larvae are white with dark heads, and pupae are small and cream-colored.
Palestriped flea beetle lifecycle
Mated females lay eggs in the soil near the base of food plants each spring. When they hatch, larvae move into the soil where they feed on roots for 2 or 3 weeks before pupating. Pupae match hatch mid-summer through early autumn. There can be up to three generations each year.
After pupating, adults emerge and begin feeding on the underside of leaves. As temperatures drop, adults look for sheltering dirt clods, plant debris, and weeds to protect them through winter.
Palestriped flea beetle damage
While the larvae chew on the roots, adult beetles are the ones that cause the most damage. Palestriped flea beetle feeding looks a lot like shot hole disease. It can also be mistaken for cavity spot. As beetles gnaw on the underside of leaves, the damaged areas die off and create small irregular holes. When this feeding occurs on seedlings and young plants, the damage can significantly reduce yield over the life of the plant or kill them outright.
How to control palestriped flea beetles
Pesticides generally don’t work against flea beetles. You can reduce the likelihood of them setting up shop in your garden by keeping attractive weeds away from your plot. By attractive, I mean members of the same plant families the beetles prefer. You can use that same logic turned around by employing trap crops to lure palestriped flea beetles away from garden plants you’d rather they left alone.
Monitor seedlings twice a week for signs of palestriped flea beetle feeding. Knock any beetles you find into a container of soapy water. Once plants are established, a little damage won’t cause significant problems.
When it’s time to put the kettle on, few of us consider the source of those tea leaves unless we’re drinking herbal tea. And that's only because we use the names of the herbs when we buy them.
Herbal teas, such as peppermint or chamomile, are fragrant and earthy. I enjoy them regularly. But, in preparation for my first trip to London, I decided to drink the black tea of my earlier years. The tea bags look the same. [Did you know that many tea bags contain plastic? I didn’t either until recently. Yuck.] The way one makes tea is the same. But black tea is one of those things that somehow feels out of reach and unproducible at home, like paprika. Of course, that feeling led me to learn more about tea plants.
The tea plant family
If you read The Daily Garden regularly, you know that I like to learn about plant families. Much like human families, plant families have traits in common. Knowing about those traits can help in the fight against pests and diseases. It reduces your gardening workload, too. The tea plant family is no exception.
The tea family (Theaceae) is primarily native to China and East Asia, though there are a handful of North American residents. Members of the tea plant family are now grown globally in warm regions. This family of flowering shrubs and trees includes tea and ornamental camellias.
I wouldn’t have thought my bright pink camellias were related to what was in my teacup, but they end up having a lot in common. Both plants have simple, glossy leaves that alternate along the stem and end with what’s called a Theoid leaf tooth. You’ve probably seen these before. When the medial vein expands and becomes slightly opaque and congested at the end of the leaf, with no other veins involved, you have a Theoid leaf tooth.
Tea plants and camellias are both evergreens. They both have showy pink or white flowers. And those flowers are protected at the base with a calyx made with five or more sepals. Both plants can have lots of stems. While you wouldn’t see it without a microscope, both plants produce pseudopollen. Pseudopollen looks like the real thing, and it attracts and provides food for pollinators, but it doesn’t contain any genetic information.
Other members of the tea family have the same characteristics. A couple of North American natives are Georgia’s Franklin tree (Franklinia alatamaha), which is now extinct in the wild but still cultivated as an ornamental, and Loblolly-bay (Gordonia lasianthus), found throughout southeastern North America are both members of the tea family. But what about that cup of tea?
Tea plant basics
Tea plants (Camellia sinensis) are evergreen shrubs that can grow six feet tall. They have deep taproots and use a lot of water. This makes sense because their native regions get an average of 50” of water a year. Those regions are also a lot warmer than, say, Minnesota. Tea plants can be grown outdoors in Zones 7-12 or indoors year-round. Because tea plants have large taproots, they need large containers.
There are four unique tea plant varieties. Chinese small leaf tea (C. sinensis var. sinensis) and Chinese large leaf tea (C. s. var. assamica) are the most commonly grown tea varieties. There are thousands of cultivars.
Tea plants grow more slowly and produce the best flavor at higher elevations. They prefer moist, nutrient-rich, slightly acidic soil with a pH of 5.5 to 6.5 and full sun. It may take 4 or 5 years of growth before you start harvesting leaves from your tea plant, but it will grow and produce for another 40-100 years.
Harvesting tea leaves
Harvesting tea leaves can be a labor-intensive process. Young tea plant leaves and terminal buds (flushes) are harvested by hand to make high-quality tea. Lesser teas are harvested by machine. Depending on the local climate, harvesting may occur twice a year or as often as every week or two.
After being picked, leaves are allowed to wilt for a while. Then they are bruised or torn. Among professional tea producers, they are disrupting or macerating the leaves. Damaging the leaves this way allows enzymes to start oxidizing or breaking the leaves down. Next, leaves are rolled between human hands or crushed by machinery. Then the leaves are heated to halt oxidation. This process is called the green kill. The leaves are then dried completely, packaged, and sent to grocery stores, restaurants, and tea shops.
Tea plant problems
Tea plants are susceptible to bacterial diseases, including crown gall and bacterial canker. Nematodes and caterpillars commonly attack tea plants. But the biggest threat to tea plants comes from fungi. Anthracnose, armillaria root rot, black rot, and damping-off are a few fungal diseases that strike tea plants.
Like camellias, tea plants make lovely additions to tea gardens, patios, and sunny rooms, depending on where you live.
If you grow milkweed for monarch butterflies, you need to know about milkweed weevils.
Like many other gardeners, I have researched and planted native milkweed species for my region to help offset the habitat loss of monarch butterflies (Danaus plexippus). Unfortunately, milkweed plants (Asclepias syriaca) are the food of choice for more than just butterflies.
Milkweed weevils are tiny black specks that damage milkweed plants, making them distasteful or even inedible to monarch larvae.
There are tens of thousands of weevil species around the world. They all cause trouble. Boll weevils are estimated to have cost the cotton industry more than $100 billion over the past century, with inflation taken into account. On the other hand, some weevils are being employed to eradicate invasive plant species, so maybe they’re not all bad. And maybe the weevils consider monarchs to be pests.
Milkweed weevil species
There are two milkweed weevils: regular milkweed weevils (Rhyssomatus lineaticollis), which prefer the leaves of common milkweed, and stem milkweed weevils (R. annectans), prefer milkweed stems food and egg-laying.
Milkweed weevil description
All weevils are small gray or black beetles. When I say small, I mean less than one-quarter of an inch. They may look like nothing more than specks. Get closer to see that they have long snouts called rostrums. Within those snouts are chewing mouthparts that take a significant bite out of buds, seeds, and stems.
Like many other weevils, these evil twins have elbowed antennae with knobs on the ends, hard-scale bodies, and those snouts. Milkweed weevil larvae have tiny antennae, some scales, and no legs.
Milkweed weevil behavior
Milkweed weevils are nocturnal. They start eating tender new leaves and then move towards the buds and stems, where they lay eggs. They may also sever small petioles as they feed. When threatened, these pests play dead. Don’t be fooled. As soon as you turn your back, they’ll return to feeding and damaging your milkweed.
Managing milkweed weevils
The first step in any pest control problem is identifying the culprit. And milkweed plants are not without defenses of their own. As a milkweed weevil chews on a leaf, the plant starts oozing sticky, caustic latex. In some cases (pictured below), the plant can kill the pest without any help from gardeners.
Remember those boll weevils we mentioned above? Well, not too long ago, some researchers were trying to develop a pheromone trap for them when they discovered that milkweed weevils were more attracted to the traps than the intended victims. So, there are pheromone traps for milkweed weevils. You can also knock them into a container of soapy water.
Some people say you can inject certain nematodes into the stems of plants infested with milkweed stem weevils if you’re into that sort of thing, but I couldn’t find any science to back up the claim, and they never mention which nematode. [There are more than 25,000 species.]
Check your milkweed plants regularly for those tiny black specks. And remember, if you are planting milkweed for monarch butterflies, be sure to plant native varieties, not tropical varieties. It matters a lot if you’re a monarch.
Large Yellow Underwing Moths
These moths may be larger than many others, but they are not yellow. They are brown. And their larvae can be devastating to your garden.
There are several types of yellow underwing. Whichever species you come across, these are airborne adult cutworms. Cutworms are destructive caterpillars that cut prized garden plants down at the soil level during the night. Native to Eurasia and North Africa, this invasive pest is now firmly established throughout North America.
Large yellow underwings (Noctua pronuba) are rarely seen. I surprised the one pictured above out of my flowering beets with a spray from the garden hose. I was able to capture it and add it to my collection.
Large yellow underwing description
As far as moths go, large yellow underwings are sturdy. They have some heft to them. While my specimen was very brown, other members of this family can range from light brown to nearly black. Like other moths, they rest with their wings held flat, in tabletop fashion, over the body. [Butterflies tend to hold their wings upright when at rest.] Large yellow underwings have a wingspan of 2” to 2-1/2” across.
The larvae start as tiny gray caterpillars but grow to 2” long. They can be green or gray-brown, with darkened heads. Brown cutworms have bands of gray or brown that run the length of the caterpillar. When disturbed, they curl up into a C-shape.
Large yellow underwing lifecycle
Adult moths generally fly from July to September, but those flight patterns have expanded in recent years. Females lay clusters of tiny, pearl-like eggs in the soil or on host plants. If you were to look closely, you would see that these eggs look ribbed or have a netting pattern.
Eggs start white but soon turn grayish-pink. After they hatch, these tiny caterpillars may feed a little bit, but the real damage occurs as temperatures rise. Just when your tomato, spinach, and strawberry plants are coming to life, cutworms emerge at night, devouring young leaves and severing new stems. After eating their fill, they return to the soil. There, they surround themselves with hard, rust-colored oblong cases where they pupate. Adult moths emerge 2-3 weeks later, and the cycle begins again.
Adult large yellow underwings are attracted to butterfly bush, ragwort, and red valerian. But it is larval feeding that causes all the damage. Larvae feed on the stems and leaves of young plants. The following plants (and other members of the same families) are commonly used as food by large yellow underwing larvae:
• Beets (Beta)
• Broccoli and cabbage (Brassica)
• Carrots (Daucus)
• Grapes (Vitis)
• Lettuce (Lactuca)
• Strawberries (Freesia)
• Tomatoes and potatoes (Nightshade family)
Carnations, chrysanthemums, dahlias, dandelions, freesia, gladiolas, sweet violet, and grasses are also vulnerable to cutworm feeding. But planting calendula in your garden will help to deter these pests.
Controlling large yellow underwing moths
These flying pests are attracted to lights at night. If you feel so inclined, you can sit on the porch with a butterfly net and put an end to their destructive ways with a container of soapy water or a garden shoe. Or, you can go out at night with a flashlight and handpick the buggers before too much damage is done. You might also use a garden claw to gently disturb the soil around affected plants. The larvae tend to stay near the surface, so you may be able to find and remove those pests that way. Drench tests can also flush cutworms out of the soil.
A while back, lectins made their way into the media. They were held responsible for practically every illness known to man. Thanks to Steven Gundry’s book, The Plant Paradox. He claimed that lectins were responsible for disease and obesity. He was wrong. There is no scientific evidence to support his claims. But lectins can hurt you.
Let’s learn the truth about lectins and how they impact the plants in your garden (and your body).
What are lectins?
Lectins are protein molecules that bind to specific carbohydrates. The word lectin comes to us from the Latin word for choose, which is a good description of what scientists believe lectins do inside your plants. While more research is needed, lectins appear critical to cell recognition.
Plants use lectins to facilitate interactions between pollen and the stigma during pollination. They also play a role in maintaining seed hull integrity. When a plant cell bumps into harmful bacteria, beneficial microorganisms, or fellow plant cells, lectins initiate the proper response. That response can be anything from toxic warfare, a welcome mat, or cell-to-cell communication.
Lectins as toxins
The toxic warfare response may be what triggered Mr. Gundry's belief that lectins cause human disease. Lectins are toxic in specific situations. They are the reason why beans and other legumes are difficult for us to digest. That’s why we cook them. The heat breaks down the lectins (among other things).
Can lectins hurt me?
Some plants contain enough lectin to cause illness or even death. Castor oil beans are one example - but who wants to eat those?
In most cases, we typically can not eat enough lectin-containing plants to hurt us.
As always, take sensational media with a grain of salt. And cook your beans.
We’ve all heard more about pandemics in the past couple of years than any of us would care to know. But the plants in your garden are in a PAN-demic of their own. PAN is short for peroxyacetyl nitrate. [You can see why we call it PAN.]
PAN is second only to ozone in its toxicity to plants. As a type of air pollution, it is especially hard on smaller plants and young leaves.
What is PAN?
PAN is created when sunlight hits car exhaust and industrial gases. We won’t get into the chemistry of it or the different types of PANs. It’s enough to say that hydrocarbons interact with nitrogen in the air, creating problems for plants. PANs occur in high-traffic areas such as Los Angeles, but their effects are felt all along the western U.S. seaboard and in many other industrialized regions.
Like other garden issues, not all plants are affected equally. Beets, cane fruits, celery, dill, endive, escarole, fennel, lettuces, melons, oats, peppers, pinto beans, potatoes, spinach, sunflowers, Swiss chard, and tomatoes are all vulnerable to PANs in the air. If you live in an area where PAN might be a problem, broccoli, cabbages, corn, cucumbers, lima beans, onions, radishes, sorghum, and wheat should perform better than more sensitive plants.
Symptoms of PAN
PAN causes the tissues that make up the underside of leaves to collapse. This damage may appear as bronzing, glazing, or silvering. These discolorations commonly appear in bands or blotches. When pinto beans and tomatoes are affected by PAN, the tissue collapse may affect the whole leaf. In grasses, such as corn and millet, leaves affected by PAN look bleached. Chlorosis, early maturity, premature leaf drop, stunting, and weather flecking also occur.
PAN can combine with ethylene to make matters worse. Healthy plants produce ethylene as part of the ripening process. But ethylene is also found in vehicle exhaust and industrial fumes, which means there is often too much of it available. Ethylene acts as a plant hormone. And we’ve all seen what happens when people take too many steroids.
Symptoms of PAN combined with ethylene include downward leaf and stem curling (epinasty), inward petal curling and the failure of buds to open (sleepiness), and stunting. Color breaking in blossoms and early petal drop may also occur.
Bottom line: air pollution is bad for all of us.
A mosquito the size of an elephant?!!? Now that would be terrifying.
Luckily for us, elephant mosquitos, and their siblings in crime, treehole mosquitos, are mosquito predators. This means they eat mosquito larvae. They eat a lot of mosquito larvae. Each one may consume 5,000 mosquito larvae before they reach adulthood.
And you don’t need to start worrying about the adults either. Instead of blood, adults use sugar from nectar to produce their eggs.
Predatory mosquito description
Elephant mosquitos (Toxorhynchites rutilus septentrionalis) and treehole mosquitos (T. r. rutilus) are larger than blood-sucking varieties. The wingspan is similar to an American quarter. They are also more brightly colored than biting mosquitos. These predators have bright yellow markings with green or blue metallic bars. The larvae are also larger than their blood-sucking counterparts.
Predatory mosquito development
Predatory mosquitos start out like other mosquitos. White, football-shaped eggs are laid in tree cavities and other spaces that contain water. They also use all the other stagnant waters that pesky mosquitos use: flower pots, pet watering bowls, patio furniture, and tires. Mosquito eggs are the size of a grain of sand.
The eggs hatch into larvae. Predatory mosquito larvae go through four growth stages or instars. As they grow, they feed on anything nearby that moves, including each other. And this presents a problem.
The problem with predatory mosquitos is that you generally haven’t been able to buy them. Unlike our cheery ladybugs and voracious praying mantis, predatory mosquitos don’t take kindly to mass commercial breeding programs. They simply eat each other. Instead of hundreds of helpful predators, you’d end up with a handful of overfed gluttons. Scientists are working on this. For now, the best thing you can do is maintain a healthy environment with lots of biodiversity and use pesticides judiciously.
While Bacillus thuringiensis (Bt) will kill biting mosquitos, it doesn’t seem to affect their predatory cousins.
Plants and air pollution
As someone who grew up in the San Fernando Valley of Los Angeles in the 1960s and 70s, I am no stranger to air pollution. I recall days when we were required to stay indoors at school because the air quality was so bad. And, no, we did not have air conditioning. It was awful. Luckily, I had a great 6th-grade teacher, Ms. Melching. She would dim the lights and read to us about blizzards. It helped. But the polluted air gave us headaches and respiratory problems.
Plants need clean air to grow and thrive too. But it can be hard to recognize the damage caused by air pollution. It often looks like disease, heat stress, mite feeding, nutrient disorders, or water stress. If you’ve ruled those out, it’s time to consider air pollution.
Types of air pollution
Air pollution is estimated to cost US agriculture over one billion dollars annually. This damage can be chronic or acute. The smoky yellow skies from fires or fumes from a chemical spill fall under the acute category. More likely, your plants are feeling the effects of long-term exposure to low levels of pollutants from industry, power generation, and vehicles. The most common pollutants include nitrogen oxides, ozone, peroxyacetyl nitrate (PAN), and sulfur dioxide. Ammonia, chlorides, chlorine, and fluorides may also be in the mix that’s choking your plants.
The most common signs of some of the major pollutants are as follows:
Protecting your plants
Healthy plants are more able to protect themselves, so keep them well fed and watered. Also, the damage is most likely to occur during warm, humid days with no wind. Monitor air quality in your area and give your plants a light shower from the hose on days with poor air quality.
You can also help your plants (and yourself) by learning about the industries currently or recently active in your area (or upwind). And think about how you spend your money. Are you supporting companies that protect the environment or opting for the cheap stuff? It’s up to you, but we're all breathing the same air as our plants. Just sayin'.
We’ve all heard of collard greens, but what if you could grow these healthful leafy greens year-round? It ends up you can.
There are several types of tree collards. The two most common are tree cabbage or tree kale (Brassica oleracea var. acephala) and Jersey cabbage (Brassica oleracea longata). These cousins of broccoli, Brussels sprouts, cabbage, cauliflower, kale, and kohlrabi are not annuals that must be replanted each spring. Instead, they are perennials. And they lack the oxalic acid that makes other members of this group taste bitter.
Tree collards description
Instead of shrub-like mounds of kale or collard greens, these tall stalks look something akin to a palm tree. They can grow 8–10’ tall, but most people trim them to half that height to keep them bushy and less likely to fall over. Tree collards grow as a single stalk with a crown of large, purplish-green, edible leaves. The more purple you see, the sweeter they taste. Stems often have a white, powdery coating that is said to reflect damaging summer sunlight.
These shrubs can live for 20 years but are most productive when replaced after 4 or 5 years. Tree collards can withstand winter temperatures as low as 20°F (-7°C), but they grow best in USDA Hardiness Zones 8–11.
How to grow tree collards
Tree collards are best grown from certified pest- and disease-free rootstock, planted in either spring or autumn. These plants are sturdy and do not require special treatment once established. If you know someone who already has tree collards, ask for some cuttings. Cuttings should be 4–6” long and about twice the diameter of a pencil. This method requires daily light watering and can take 4–8 weeks, so don’t give up. Tree collards can also be grown from seeds.
While tree collards prefer growing in the ground, you can also use a large container that is at least 15 gallons in size.
Where to grow tree collards
Tree collards should be three feet apart. And they will readily cross-pollinate with other members of the cabbage family. Tree collards grow best in nutrient-rich, slightly alkaline soil.
Tree collards thrive in dappled shade and prefer protection from afternoon sunlight. They do not grow well in full shade.
Tree collards are relatively drought tolerant but perform best in well-aerated soil with regular mulching and top dressing. And they’ll grow bigger and better with regular irrigation in summer. It’s always a good idea to have your soil tested by a reputable lab before fertilizing. Adding too many nutrients can cause more problems than nutrient deficiencies.
Tree collards pests and diseases
These plants are relatively trouble-free. Imported cabbageworm butterflies are the primary pest of tree collards. Handpicking the caterpillars and extermigating the eggs are your best control methods. Snails and slugs are less of a problem than seen on their shorter cousins. And aphid infestations tend to be localized and short-lived. Let the ladybugs and other beneficial insects take care of those pests for you. Ladybugs won’t be able to do anything about the deer and other herbivores, though.
Powdery mildew is a common problem for tree collards, so maintain good airflow and keep your plants healthy.
To keep your tree collards attractive and productive, it’s a good idea to prune out stems as you harvest leaves. If you want your tree collards to reach full height, you may want to stake them upright. When growing naturally, they tend to fall over, creating an arching tangle similar to a blackberry bramble.
Natural Root Grafts
We’ve all heard social networks help us to be healthy and successful. It ends up that trees have been networking quite intimately for a very long time.
Tree networking takes two forms. They frequently share nutrients indirectly, using soil microorganisms as go-betweens. And they fuse their root systems in natural root grafts, called anastomoses.
How do roots graft?
Natural root grafts occur when relatively small roots of two different trees come into contact with each other. As they grow, they fuse, creating mutually accessible cambium layers and vascular bundles that allow them to share water, nutrients, and the products of photosynthesis.
Why does this happen?
More than 150 plant species exhibit natural root grafts, according to researchers. There is debate about whether this occurs due to overcrowding or if plants purposefully graft their roots onto neighboring roots. There is also debate whether this action is beneficial or verging on parasitism. Most researchers lean toward the mutually beneficial explanation. Potatoes and strawberries frequently graft their roots onto neighboring plants of the same species. Surprisingly, some natural root grafts are between different species.
Benefits of natural root grafting
Natural root grafting provides several benefits to all parties involved. Those benefits include improved stability and water and nutrient sharing. These benefits help keep neighboring trees healthy, making them more resistant to wind and herbivore damage. In one study, trees with natural root grafts were found better able to recover from a spruce budworm attack.
Tree root grafting allows groups of trees to share water and nutrients. It also forces them to share soil-borne pests and diseases, such as Dutch elm disease and apple proliferation.
For me, this is yet another example of the amazing processes going on underground. I was stunned to learn that plants can hear. I wonder what will be discovered next.
Drinking and drought
Summer BBQs often involve a spilled beer or two, but did you know that might be helping your drought-impacted plants? Read on!
Climate change and food production
Climate change is having a growing impact on food production worldwide. [Sorry, I couldn’t resist.] Not all of our groceries grow well in these rising temperatures. And drought is reducing crop yields all over the place. Scientists estimate that corn and wheat crops will be seriously affected by 2030, so a lot of research is being done to see if bigger root systems or other modifications can help plants grow with less water and in higher temperatures.
Plants respond to heat
When plants are hot and dry, they protect themselves by closing pores found on the underside of leaves. These stomata control the rate of gas exchanges used by plants in photosynthesis. This respiration can be slowed by as much as 50% during periods of extreme heat. Unless your plants are drunk.
Pints and plants
Recent research has found that many plants can thrive during drought if they are given ethanol. Ethanol is alcohol. It ends up that plants produce alcohol when they don’t have enough water. This fact led some researchers at the RIKEN Centre for Sustainable Resources Science to wonder if the same processes could be used to protect plants.
Alcohol abundant and cheap to make. Did you know that U.S. bars mark up their alcohol by an average of 400-500%? But back to the plants.
Researchers compared wheat and rice plants that had been treated with alcohol to those without. The plants were deprived of water for a couple of weeks in summer. Only 5% of the untreated plants recovered, while 75% of the alcohol-treated plants were able to resume growing once watered. Those are some significant numbers!
The scientists radio-tagged the alcohol so that they could see where it went within the plants. Plants that were given alcohol started behaving like they were in a drought even before the water was cut off. This helped them to be better prepared than their teetotaling brethren. Not only did they make better use of the water they had, but they also used the alcohol to create sugars to provide themselves with energy and perform more photosynthesis, even though their stomata were closed.
Now, this doesn’t mean you should go around giving your pumpkin plants shots of tequila. That would be a bad idea. What it does mean is that an occasional spilled beer might not be such a bad thing and we should all be on the lookout for more specific instructions as the research continues.
Bacterial Soft Rot
Bacterial soft rot destroys more crops than any other bacterial disease.
Commonly occurring in cruciferous, cucurbit, nightshade, and onion families, bacterial soft rot also causes severe pitting in carrots.
Rather than a single disease with a simple cause, bacterial soft rot refers to a collective of bacterial rots caused by Dickeya dadantii (previously known as Erwinia chrysanthemi), Pectobacterium carotovorum, and various Bacillus, Clostridium, and Pseudomonas bacteria. Whichever critter starts this problem, the soft tissues of buds, bulbs, corms, petioles, rhizomes, stems, and tubers are liquified and your crop turns to mush.
Symptoms of bacterial soft rot
Like other bacterial diseases, bacterial soft rot is easily overlooked at first. As the disease progresses, water spots start to form on soft tissues. Unlike the whitish splash marks left on old wooden furniture, these spots grow larger, softer, and start to sink. As interior tissues break down, these damaged areas may ooze and start changing color. Discolorations can range from cream to black. And they smell bad.
Bacterial soft rot management
Poor drainage, waterlogged soil, and insufficient airflow all set the stage for bacterial soft rot. Infected plants must be destroyed and removed. Prevention is worth the effort. The following good cultural practices can significantly reduce the likelihood of bacterial soft rot affecting your plants:
• Use certified clean seeds and seedlings.
• Quarantine and harden off new plants.
• Install resistant varieties.
• Plant at the appropriate times and correct depths.
• Use recommended plant density.
• Monitor plants regularly for signs of infection.
• Provide adequate airflow through proper pruning.
• Irrigate properly, allowing the soil to dry out between waterings.
• Employ crop rotation to reduce overwintering bacteria.
• Remove weeds.
• Avoid working crops when they are wet.
• Remove infected plants and dispose of them in the trash.
• Clean and disinfect tools regularly.
If bacterial soft rot continues to be a problem in specific areas of your garden, use that space for plants that are generally not susceptible. That list includes beets, corn, and snap beans.
You can grow a surprising amount of food in your own yard. Ask me how!
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