Tillers are used to steer boats. Tillers are used to plow the soil. But the word tiller can also refer to a type of lateral shoot that grows at the base of corn and other grass or cereal grains (Poaceae).
Tillers are a form of vegetative reproduction.
Tillers are often seen in barley, oats, and wheat. When they occur on corn plants, they are frequently called “suckers.” Children were traditionally sent into the fields to remove corn tillers. But was this really necessary?
Grass family growth
Corn and other grass plants generally send up central stalks with leaves wrapped around that main stem. Sometimes, new branches start growing from the lower five to seven stalk nodes, or from below ground. These "daughter plants" are clones that are able to grow into independent plants with their own root system, leaves, nodes and internodes, and even their own ears (female flowers) and tassels (male flowers).
When this type of new growth occurs higher up the stalk, they tend to grow into ear shoots which are morphologically different from tillers. Ear shoots have shorter internodes, smaller leaves, and they always terminates in an ear, rather than a tassel.
Tillers can sometimes get confused as they grow, terminating with a flower that is both male and female. These are known as tassel-ears.
Research has shown us that tiller development indicates optimal growing conditions. Abundant water, sunlight and nutrients create a situation in which the plant has enough reserves to invest in tiller development. While tillers may compete with their parent plants, they usually don’t have enough of a growing season to develop harvestable ears.
Tillers can also occur in response to damage. When the main stalk is damaged early in its development, whether through insect or herbivore feeding, frost or hail, or mechanical injury, tillers can take over and may even develop harvestable ears, though this is rare.
In most cases, tillers have little or no effect on crop size. But if your kids are driving you nuts this summer, you can still send them out to remove tillers.
What is it? How does it work? And are all the beneficial claims about compost tea true?
Let’s find out.
What is compost tea?
Compost tea is a brewed extract of bacteria, fungi, micro arthropods, nematodes, and protozoa made from compost. Traditionally, compost was placed into a permeable bag, which was then placed in a container filled with water until the water turned black. That water was then used to irrigate both indoor and outdoor plants as a liquid organic fertilizer. The idea behind it was that all the nutrients and microbes would end up in the water, easier for plants to absorb. Makes sense, right?
That was the old-fashioned method of making compost tea and it resulted in a soup of anaerobic (without oxygen) microbes and nutrients. Modern marketing and manufacturing now offer compost tea brewing kits, or ready-made compost tea. These kits use energy to aerate the tea. The differences between aerated and nonaerated compost tea will be discussed in just a moment.
Compost tea claims
Compost tea is said to be a mild food additive for plants, much like our daily vitamin pills. Proponents of compost tea claim it makes plants and the surrounding soil healthier, reducing the need for fertilizer. Compost tea is also said to improve soil water retention, reducing the need for irrigation. The addition of all those microorganisms is supposed to improve soil structure, reduce compaction of heavy clay soil, and help sandy soil retain water and nutrients. But wait! There’s more!
Using compost tea is also said to stimulate root growth and counteract the negative effects of chemical-based herbicides, insecticides, and pesticides. And foliar (leaf) sprays of compost tea are said to stimulate the growth of beneficial microbes on leaf surfaces, reducing the chance of disease and pest damage.
Science and skepticism
Like most claims that sound too good to be true, compost tea does not hold up well to scientific testing.
First, the availability of nutrients is misleading. Unlike slow-release fertilizers and composts, compost tea risks dumping large (variable) amounts of nitrogen, potassium, and other nutrients into the soil all at once. Plants can only absorb so much at one time, so many of those nutrients (assuming there are any) end up in ground water causing eutrophication, or nutrient contamination.
Second, claims of disease prevention are greatly exaggerated. Just because something works in a lab does not mean it will continue to work in your garden. There are simply too many other factors at play.
It’s true. Some studies have shown that foliar sprays of nonaerated compost tea do, in fact, reduce the incidence of some diseases in laboratory settings. Disease severity is not altered, and results are less clear out in the real world garden. Also, some fungal diseases were reduced with foliar sprays of aerated compost tea. Those diseases were growing on Petri dishes. In greenhouse testing, the diseases were not affected. Other studies have shown that foliar sprays of aerated compost tea actually made diseases of apples and potatoes worse.
Like probiotics, the microbial and nutritional makeup of compost tea is extremely variable. It is almost impossible to say what each batch actually contains. In fact, some compost teas can contain human pathogens. [Can you say e. coli or Salmonella?]
The bottom line
According to the U.S. Environmental Protection Agency, it is against the law to sell unregistered substances for use as pesticides. Compost tea is not registered in this way, so any claims made about its effectiveness as a pesticide are false. Aerated compost teas have no documented ability to suppress disease.
Rather than wasting time and effort on something that lacks a scientific basis, use that compost the way nature intended. Apply a nice thick layer of aged compost as a mulch on your planting beds and let the worms, microorganisms, and other natural processes take advantage of billions of years of evolution.
The benefits of mulching with aged compost are well-documented. And if your plants need a little nutritional boost, I suggest fish meal.
Today we are going to delve deep into the soil under our feet and talk about something you will probably never see.
Discovered in 1977, archaea [are-KI-ah] used to be classified as bacteria and were called archaebacteria. Scientists now know they are their own group. Their name means “ancient things” and they are believed to be one of earth’s oldest life forms, first occurring some 3.8 billion years ago.
Archaea are completely new to me. But it ends up they are very important to soil and plant health, so let’s see what we can find out.
In the world of living things, there are three basic groups: eukaryotes, bacteria, and archaea. Eukaryotes have nuclei and organelles. Bacteria and archaea do not. Archaea and bacteria are prokaryotic. Prokaryotes are primitive, single-celled organisms with no organelles or nucleus. Archaea are slightly more complex than bacteria, but not by much. Simple as they may be, there are more bacteria and archaea in the soil than any other microorganism and they are critical to nutrient cycling.
Archaea are found pretty much everywhere on Earth, including some pretty extreme environments. These microscopic beings can tolerate hot springs, salt marshes, and even deep, frigid ocean environments. Some species live inside of plankton and termites, as well as in our guts and on our skin. In fact, archaea make up 10% of the microbes in our digestive systems, but I digress.
Types of archaea
Archaea come in several shapes and sizes. There are flat archaea, square archaea, and cylindrical archaea. Archaea can range in size from 0.1 micrometers (μm) to 15 μm. For perspective, an American dime has a diameter of almost 18,000 μm.
In some cases, archaea will form chains that can be 200 μm long. These chains form biofilms. Scientists are unsure about why these chains form, but many believe that they facilitate communication and nutrient exchanges, much the way other soil microorganisms work to share nutrients with nearby plants.
Archaea are classified by what they eat. These nutritional groups choose from an extensive menu. There are phototrophic archaea that use sunlight for food. Other archaea break down inorganic minerals such as carbon and sulfur for food. Yet other archaea eat sugar, ammonia, and even hydrogen gas. [I guess when you’re as small as they are, a molecule of hydrogen probably looks like a potato chip.]
As they feed, archaea become major players in nutrient cycling. They fix atmospheric nitrogen in the nitrogen cycle, make sulfur available to plants in the sulfur cycle, and are essential to decomposition and the carbon cycle. Put simply, without archaea, many plants would starve.
Plant growth is most often limited by insufficient nitrogen. There’s plenty of nitrogen floating around in the atmosphere, but plants can’t use it in that form. Instead, atmospheric nitrogen needs to be “fixed” into compounds, such as ammonia, that can be used by plants. Archaea help fix that nitrogen.
While bacteria and fungi can cause several garden variety diseases, archaea are not known to be pathogens or parasites. On the contrary, they tend to be very helpful wherever they are.
So what can we, as gardeners, do to protect and provide for these microscopic helpers?
1. Avoid using chemicals that can disrupt natural processes.
2. Avoid using unnecessary herbicides, insecticides, and pesticides.
3. Add organic material to your soil through top dressing and mulching.
4. Only apply soil amendments as indicated by a lab-based soil test.
Now you know,
It’s still pretty cold outside for most insects, but it’s always nice to be able to recognize signs of spring.
Gulf fritillaries (Agraulis vanillae) are cheery orange butterflies whose appearance marks the changing seasons. These butterflies overwinter in the southern states and South America, returning to more northern territories as temperatures rise.
Affectionately known as gulf frits, these garden visitors usually appear in early April, flitting erratically from flower to flower in search of nectar and mates. Eggs are most commonly laid on types of passionflower (Passiflora). When those eggs hatch, caterpillars begin feeding on the leaves of the host plant. Heavy infestations can cause defoliation, but this is rare.
Gulf frits are medium-sized butterflies with bright orange wings and black markings. They have a 3” wingspan and the forewings are elongated, with three black-rimmed white spots on the top side. The underside is brown with elongated silvery spots.
Eggs are yellow and laid singly on or near passionflower plants. Larvae are bizarre looking. Caterpillars start out bright orange and covered with black barbed spikes. Those colors slowly change as it grows. The pupa looks like someone wadded up a tiny brown paper lunch sack. The truth is, they need all the protection they can get.
The life of a gulf frit is fraught with danger. Scrub jays and other insect-eating birds snatch them from the air. Lady beetles, spiders, and wasps eat their eggs. Parasitoids and wasps attack caterpillars and chrysalids. European paper wasps and praying mantids eat their share. If you are able to get a close look at a gulf fritillary, you will often see that their wings are ragged and torn from these dangerous encounters.
Gulf frits are not entirely helpless, however. These gentle souls have chemical warfare on their side. When predators get too close, gulf frits release foul-smelling pheromones to discourage attack. They have another pheromone they use to attract mates, but I have to assume that it smells good to other gulf fritillaries.
Smell isn’t the only aspect of gulf frit courtship. All too often we forget that in the tiny world of insects, life can be highly complex and fascinating. When a male gulf frit spots an alluring female, he lands next to her, at a 45° angle, and places his head affectionately against hers. Then he claps his wings open and shut in a something called a wing clap display until she is receptive. Males also give their mates chemical and nutrient treats, called nuptial gifts, that improve her health for better egg-laying.
To attract and provide for gulf frits, add varieties of passionflower and lantana to your butterfly garden or landscape this spring.
Dark spots on leaves can mean many things.
It may be black spot. It may be bacterial brown spot. Or it may be bacterial leaf spot.
Black spot is a fungal disease caused by Diplocarpon rosae that features round, black spots on leaf tops. Bacterial brown spot is caused by Pseudomonas syringae pv. syringae and features narrow light green borders and the centers tend to dry out and look tattered.
Bacterial leaf spot is generally caused by the Xanthomonas and Pseudomonas families of bacteria. These bacteria thrive in wet, cool soil, surrounding by plant debris and mulch. Rain and sprinklers splash these microscopic pathogens onto nearby plants. As temperatures reach 77°F to 86°F, these bacterium can start reproducing at astounding rates.
Bacterial leaf spot can kill leaves and weaken plants. This defoliation can also cause sunscald damage to fruit. Your basil, beets, eggplant, lettuce, peppers, and tomatoes are all susceptible to bacterial leaf spot. So are all your stone fruits, including almonds, cherries, and peaches.
Bacterial leaf spot symptoms
Symptoms first appear along leaf margins (edges) of older leaves as yellowish-brown spots, ¼” to ½” in diameter, that can be round or angular. These spots start out looking water-soaked and then dry. They may be seen on both the tops and bottoms of leaves and may form clusters. Regardless of the pathogen, these spots quickly turn black.
The Xanthomonas bacteria tend to produce small brown spots with yellow halos. The Pseudomonas bacteria produce reddish-brown spots. Stem streaking can also occur and you may see sunken areas in the fruit. These sunken areas are open invitations to other pests and pathogens.
Bacterial leaf spot control
Bacterial diseases can be devastating, but bacteria tend to be relatively weak pathogens. Unlike the more warrior-like viruses and fungi, bacteria generally need an opening to get inside a plant. Those openings can be caused by rubbing branches, wind damage, or insect and herbivore feeding. That sort of thing. By keeping your plants’ protective layers intact, you can significantly reduce the chance of many bacterial diseases taking hold.
That being said, there are other steps you can take to prevent bacterial leaf spot:
There are no effective chemical controls for bacterial leaf spot.
If you see spots on your leaves, take a closer look. See if you can determine the cause. And the cure.
I always thought that chervil was a delicate, shade-loving herb in the carrot family, which it is.
The name chervil can also refer to a root vegetable from the same family. Digging even deeper,
I learned that the same name can also refer to several other plants, but we're going to focus on the first two. For now.
The name chervil is probably so popular because it comes to us from the Ancient Greek words for "leaves of joy". How's that for a garden addition? Makes me want to grow them just for that. Let's see if we'll want to grow them for other reasons, as well.
Chervil, the herb
Chervil, the herb, is also known as French parsley or garden chervil, is more delicate than parsley, with a light licorice flavor. Chervil (Anthriscus cerefolium) is used along with chives, parsley, and tarragon to make fines herbes and it is commonly used to season poultry, seafood, soups, and sauces.
These plants grow 12-30" tall and readily reseed an area, left on their own. Like other umbellifers, chervil plants have hollow, ribbed stems, divided leaves, long, sheathed petioles (leaf stems), and flat seeds. Edible chervil flowers attract many beneficial insects, so these plants are commonly included in butterfly gardens and tea gardens.
Chervil prefers partial shade in areas where temperatures are under 65°F and full shade in areas that go above 80°F, making chervil a nice addition to stumperies and shade gardens.
Chervil can be grown in USDA Hardiness Zones 5-9 when temperatures are above 60°F. Chervil does not transplant well, due to its taproot, so seeds should be planted in place. This is a cool season crop that needs moisture. Seeds should be planted 1" deep and 6-12" apart. In 10-14 days, you should see signs of life. In 45 days or so, your chervil will reach harvestable size.
Slugs and snails will be your biggest problem
Chervil, the root vegetable
Native to middle- and southeastern Europe, this root vegetable goes by several names: bulbous chervil, parsnip chervil, tuberous-rooted chervil, and turnip-rooted chervil. Popular in Europe in the 19th century, these biennial plants grow very much like their cousins, the carrots. Instead of carrot's orange taproot, bulbous chervil (Chaerophyllum bulbosum) looks like stubby, dark grey carrots with yellowish-white flesh. Eaten raw, these tubers are said to taste similar to radishes. Once cooked, they are described as a cross between potatoes and chestnuts, with just a hint of celery and parsnip. [I haven't had them yet.] These roots are left in cold storage for a few months for starches to be converted into sugars.
Being a member of the carrot family, bulbous chervil plants produce large flower clusters that attract many beneficial insects, such as hoverflies.
Bulbous chervil grows best in loose, fertile soil that is kept moderately moist. Seeds need to be vernalized (exposed to cold) to germinate properly. Because of this, seeds are usually planted 2" apart in autumn. As temperatures rise, in spring, germination should occur.
Initial growth is a rosette of leaves close to the ground, followed by stems that can grow 2-6' tall. Roots are harvested when leaves start turning brown, usually in late summer. These are slow-growing plants that take 9-10 months to reach maturity.
Pests of bulbous chervil include aphids, carrot root flies, and voles. Diseases are similar for carrots and parsnips, with celery mosaic virus and root rots being the most common.
How about adding some leaves of joy to your garden this year?
Most of us garden because fresh fruits, vegetables, and herbs taste better.
But why do they taste better? In fact, why do plants have flavors at all?
It ends up that flavor is all about transmitters and receivers, but not the type that deliver your favorite songs or movies.
Plants have flavors because of the chemicals they use to communicate and to protect themselves. They use these chemicals to attract pollinators, inhibit bacterial and fungal pathogens, and, in some cases, slow the growth of competitors (allelopathy). Plants protect themselves by creating chemicals that make them unpalatable to attacking insects, herbivores, or pathogens.
Plants use one chemical, ethylene gas, to trigger neighboring plants to ripen. In nature, this means there will be a bunch of ripe fruit available at the same time, increasing the odds of birds and animals coming to eat and dispersing seeds. This ripening cascade works the same way leaves change color in autumn. A few trees start doing it, which triggers neighboring trees to follow suit.
But how do those chemical communications translate into flavors?
A matter of taste
When we eat something, our taste buds collect information about the chemicals in our food that dissolve (soluble). At the same time, our noses collect information about the chemicals released into the air as we chew (volatile). It ends up that these are the same chemicals plants use.
Taste and smell are inseparable. In fact, your sense of smell is estimated to be 80% of the flavor experience. Don't believe me? Try closing your eyes, plugging your nose, and taking a bite of onion - you'll swear it's an apple.
Taste is a matter of acids and sugars. There are different types of sugars. Most fruits contain varying combinations of fructose, sucrose, glucose, and sorbitol. Fructose has the most sweetness and sorbitol has the least.
Our taste buds sort sugars and acids into five categories: sweet, sour, salty, bitter, and umami. Umami is a protein flavor. Some cultures also include fattiness (oleogustus) and pungency.
Did you know that children have 10,000 taste buds and older adults only have 5,000? And dogs have less than 2,000 (which may explain why they are willing to eat some really gross things). They simply don't taste them. On the other hand, our canine companions have over 300 million smell receptors, while we have 50 million or so.
Scents and smells
We sort out aromas over those 50 million receptors using more than 650 different types of olfactory nerve endings found in our noses.
I once gave my students the assignment to create their own word. One 6-year-old student came up with 'olfactorized'. When I asked her for a definition, she said it meant being attacked by a bad smell. I miss teaching.
But how can a plant smell something without a nose? It ends up that plants have sensory receptors, much like our taste buds, that allow them to identify volatile chemicals (essential oils) floating around in the air. Dodder, for example, is a parasitic plant that uses its sense of smell to find host plants, sniffing out its favorites and avoiding sick plants.
Some of those scent chemicals include:
Clearly, there are many factors that determine a plant's flavor and some of those factors are under your control.
Genetics play a big role in flavor. If you want to taste lime, you wouldn't plant a grapefruit, right? When selecting plants for your garden or landscape, start by choosing varieties that are suited to your microclimate and that produce the flavors you want.
Environmental conditions also impact flavor. If your fruit trees and tomato plants don't get enough sunlight, they cannot produce the sugars that make them taste good. Proper tree training and plant spacing, pruning, and reflective mulches can be used to increase the amount of sunlight that reaches inner branches.
If your plants are allowed to produce too much fruit, the flavor won't be as good, either. Fruit thinning allows plants to focus their energies on quality, rather than quantity. In the same way, too much irrigation can be just as bad as not enough. During the growth phase, plants need plenty of water. As crops get closer to harvest time, you can increase flavor by reducing the amount of water available. This is called deficit irrigation.
The same is true for nutrition. If your plants get too much nitrogen, they will have more of a green, grassy flavor. Less nitrogen translates into more fruit flavor.
When you harvest your fruits also determines flavor. Most store-bought produce is harvested before it is fully ripe, to allow for shipping and storage. One of the nicest things about growing your own is that you can wait until that perfect moment before taking a bite.
What are your favorite garden flavors?
Elderberry syrup and elderberry wine are yours for the making when you grow your own.
It ends up that this group of mostly edible plants is more complex that I realized.
I say mostly because red elderberries are toxic and should never be eaten. Blue and black elderberries are toxic when unripe, but safe and delicious when ripe or cooked. And the elderberries used to make medicinal syrup are only one type of elderberry.
That being said, edible elderberries are pretty amazing. Most of us have heard about elderberry jams, jellies, pies, syrup, and wine. Did you know you can also dip flower clusters in batter and deep fry them?
These plants were traditionally used by Native Americans and the Spanish for a lot more than just food, though. The cooked "sauco" was a summer staple that needed no sweetening. Hardwood stems were used to make arrows, flutes and whistles, blowguns, baskets, and fire starters, with the pith used as tinder and stems used as twirling sticks. The wood was also used to make combs, clappers, and pegs.
Elderberries are deciduous, flowering plants (angiosperms) that grow as shrubs. Now, we're not talking about tame, well-mannered shrubs here. Some species of elderberry, given the opportunity, can grow 20-30' tall and wide, in something of a fountain shape similar to currants. And they grow quickly. [Before you panic, know that most elderberry shrubs only grow 6-12' tall.] Glossy leaves are opposite. Cream or yellow flower clusters appear in spring, followed by purple berries in autumn.
Elderberries used to be thrown in with the honeysuckle family, but scientists have discovered that they are their own group (Adoxaceae). The elderberry family is also known as the moschatel family. [If that name is new to you, you are not alone!] In the world of elderberries, it ends up names can get very confusing.
To begin, all elderberries are members of the Sambucus genus. Beyond that, there are several species worldwide, with three major elderberry species found in the U.S. Each of these species has different characteristics.
American black elderberries
American black elderberries (Sambucus nigra spp. canadensis) are native to North America east of the Rockies and they prefer cool, moist conditions, often growing naturally alongside creeks and in low lying areas.
European black elderberries
European black elderberries (Sambucus nigra spp. nigra) are found throughout Europe. These plants are not as cold tolerant as the American blacks, but more so than the blues. And it is European black elderberries that are made into medicinal syrups.
Mexican blue elderberries
Until very recently, I didn't even know there were blue elderberries. Now I get to try my hand at growing my own because a reader dropped off a big cutting yesterday! [Thank you, C.P.!]
Blue elderberries (Sambucus mexicana) are native to North America west of the Rockies and they go by a variety of names, both common and scientific. Blue elder, sweet or wild elder, Arizona elderberry, and blueberry elder are just a few of the common names. If you talk with botanists, they have another whole collection of names, but we won't get into that. Bottom line, blue elderberries prefer hotter, drier conditions than the other two. These California natives have deep roots that go in search of water. Blue elderberries also have a longer harvest season, producing fruit all summer in most cases.
Elderberries and biodiversity
Healthy environments are diverse, with lots of different things living and growing and interacting with each other. It ends up that elderberries are an extremely important food source for many native birds, including western bluebirds, cedar waxwings, and ruby-crowned kinglets. Elderberry flowers also attract a number of moths, some of which you may not want near your garden. Maybe the birds will eat them, too.
Elderberry plants produce knob-shaped, nectar-producing glands, called extrafloral nectaries, on leaves and stems. These sugar stations attract beneficial insects. This is why elderberries are often included in butterfly gardens, bee gardens, and insectaries. Insectaries can be plants or plantings that attract beneficial insects.
How to grow elderberries
Elderberries can grow in full sun, partial sun, or full shade, depending on the variety. Once established, they need very little water, maybe once a month in summer. They can also grow in areas that stay moist, but they do need medium to fast drainage. These plants can tolerate temperatures as low as 5°F, but they prefer heat.
Elderberries are best grown from seed that have been planted right away, in autumn, or separated from the fruit, dried, and then warm stratified for spring planting. If you are lucky enough to receive cuttings like I was, follow these steps:
Once established elderberry plants can be coppiced. Coppicing refers to periodically cutting trees or shrubs back to ground level to stimulate new growth for firewood, basket weaving, or other building materials, as well as fruit.
Irregular brown or white spots on leaves often mean that leaf blight has taken hold.
There are many different types of leaf blight. Leaf blight can be caused by fungal spores or bacteria and most forms of leaf blight are species specific, which means different types of leaf blight attack different plants. If you grow onions or garlic, carrots, sorghum, melons or squash, you need to know about leaf blight.
Fungal leaf blights of onions and garlic
Purple lesions, yellow to brown spots, and yellow streaks on onion or garlic may mean purple blotch and Stemphlyium leaf blight have infected your plants. These two fungal leaf blight diseases are mostly late-season problems, so you can avoid them altogether by planting early season crops, if that's an option for your area. As a double whammy, these two diseases often start growing in downy mildew lesions. A similar leaf blight attacks sorghum.
Fungal leaf blight of squash and melons
Alternaria leaf blight is a fungal disease caused by Alternaria cucumerina that attacks members of the squash family. Melons are the most susceptible, but squash, pumpkin and cucumber may also become infected. Brown smudges first appear on older leaves, near the base, or crown, of the plant. If you look closer, you will see that the damaged areas often have a yellow halo. These leaf spots may also develop concentric, target-shaped rings. Ultimately, leaves wither, curl upward, and die. Alternaria leaf blight doesn't harm the fruit, but it can interfere with photosynthesis enough to reduce crop size and can cause sunburn damage.
Bacterial leaf blight of carrots
Bacterial leaf blight is caused by Xanthomonas campestris pv. carotae and attacks carrots. Brown spots are first seen along leaf edges, or margins, and may look watersoaked. As the disease spreads, you may be able to see dark brown streaks on the petioles, or leaf stems. Flowers may also become affected. An amber-colored ooze is usually present, as well.
Bacterial leaf blight is a seed borne disease, so be sure to get your seeds from reputable suppliers. This disease is only active when moisture is present. Optimal temperatures are between 77° and 86°F. This disease does not occur when temperatures are below 65°F.
Leaf blight management
Preventing disease is nearly always easier than curing it, and this is no exception. You can prevent leaf blight in your garden with these tips:
If leaf blight appears in your landscape, toss infected plants in the trash at the end of the growing season and be sure to sanitize your garden tools between cuts. You can use common bathroom cleaners to do this.
Most of us have had the experience of discovering a forgotten something in the back of the fridge, or found a fruit in the bottom of a bowl, covered with fuzz. That fuzz is a type of fungus.
The white threads seen in soil and compost - more fungus. But there is far more to this bizarre life form than you might expect. Prepare to be blown away!
A different kingdom
We all know about the animal kingdom and the plant kingdom, but the kingdom of fungi is far less familiar. Fungi are not plants. In fact, they have more in common with animals than plants. Fungi broke off into their own group one billion years ago, and we have a lot to learn about them.
Fungi can cause and cure disease. They have been used as pesticides, poisons, and potables. They are the Earth's (and your garden's) primary decomposers and critical players in nutrient cycling and most food webs. Fungi are used in bioremediation and there are fungal spores drifting down onto your skin as you read this.
Fungi spoil our food and help it grow. They break down our buildings and provide us with building materials. Every step that you take on soil impacts approximately 300 miles of fungal threads. Every step. Three hundred miles.
There are species of ants that farm fungi for food. One type of wasp injects her eggs together with a certain fungus into the bark of host trees. The fungus starts to rot the wood, making it easier for her babies to eat when they first hatch. There are fungi living in the gut of several garden insects, including beetles and cockroaches.
Once we begin to see fungi for what they are, an extremely large, diverse group, I think we can appreciate them more fully.
The fungal family
Yeasts, molds, and mushrooms are all types of fungi, while slime molds and water molds are not. Water molds (oomycetes) are more closely related to algae, while slime molds (mycetozoa) are closer to amoeba. [Did you know that lichens are actually mutually beneficial communities of fungi and algae?]
Scientists estimate that there are millions of species of fungi. So far, we only know about 150,000 of those. An area of fungi is called its mycobiota. The study of fungi is called mycology. There are currently nine types of fungi that have been identified. You can look them up, if you're into that sort of thing, but this post is already packed with a lot of information.
One thing that makes fungi different from plants is that their cell walls contain something called chitin. Chitin is also found in fish scales, squid and octopi beaks, and insect exoskeletons. Plants do not contain chitin; they have cellulose. Some types of fungi have structures called rhizomorphs, which behave similarly to plant roots.
Fungi grow threadlike structures called hyphae. These are not chains of cells, the way algae grow. Instead, hyphae are tubes that may hold several nuclei. Hyphae grow at the tips of these tubes and often branch. Collectively, these hyphae are called mycelium. Mycelium are found in all of Earth's soil. Growths of mycelium are called colonies. There is one fungal colony in Oregon that covers 2,400 acres and is believed to be 9,000 years old. Known affectionately as the "Humongous Fungus", this specimen of Armillaria ostoyae may be the world's largest living organism, when measured by area.
Fungi do not perform photosynthesis. Like animals, they must get their food from other living (or dead) things. The different ways fungi gather their food may surprise you. In some cases, fungi do this by dissolving organic material using digestive enzymes and absorbing nutrients. Other fungi, especially pathogens, have piercing structures that can break through plant tissues, spreading disease. More on that in a minute.
Some fungi are miners. They secrete acids that dissolve tiny rocks, creating tunnels, and then harvest and store those minerals for later use.
You've probably heard me talk about mycorrhizae. Mycorrhizae are microscopic fungi that live in and around the roots of many garden plants, helping them to absorb important nutrients. These fungi also help transport inorganic, mineral nutrients from one plant to another, in exchange for sugars produced through photosynthesis. There's a great NPR radio show, From Tree to Shining Tree, which talks about an experiment that showed how trees share their food with other trees, even trees of different species. All of this happens because of soil fungal colonies. But there's more to fungi than simply decomposing and mining.
There are fungi that actively hunt springtails and other microorganisms found in the soil. They trap their prey in sticky nets and insert hyphae into living insects and nematode eggs, sucking out the innards. But they don't keep all of that food for themselves. Fully one-fourth of those insect guts and embryos end up in nearby trees. In exchange for that gift, trees give 20-80% of the sugar they produce through photosynthesis to the fungi growing in and around their roots. The fungi, in turn, hold that sugar until it is needed by the tree, or its neighbors, at which time they give some of it back.
We now know that trees send chemical messages through these fungal networks, warning neighboring trees of illness, or insect or herbivore attack. We also know that dying trees move their resources into the fungal network to be shared with other trees. We do not know who or what decides the movement of these resources or chemical messages, but I can't help wondering about the neuron-like structure of the fungal networks that help keep our plants alive. But I digress...
Fungi use several methods of reproduction and some species use more than one method. In most cases, fungi reproduce by releasing spores into air or water. A few older specimens have spores with wiggly tails called flagella. Most fungi now use cup-shaped fruiting bodies, called apothecium, which are lined with a tissue that produces spores. Spores are often ejected forcefully, with the initial force reaching nearly 10,000 g's!
Fungi also reproduce by splitting off bits of mycelium, while others use colors and odors to attract insects, which help distribute spores. Most spores are spread on wind, which is why a fungal disease in your neighbor's yard is a problem for your garden.
Fungi in the garden
Fungi perform several functions in the garden: some of them good, and some of them not so good. Fungi decompose our compost piles and provide many garden plants with nutrients. Some fungal species inhabit the leaves and stems of your grass family plants, making them less attractive to herbivores and better protected against environmental stresses in exchange for room and board.
One Swedish study even showed that it is fungi and not plants who are sequestering the majority of the carbon held in northern boreal forests. But all too often, fungi are the cause of plant disease.
Fungi as disease carriers
There are many different fungal diseases that can affect garden plants: black spot, blights, downy and powdery mildews, rusts, and wilts are just a few. More often than not, the presence of too much moisture is the reason why fungal disease takes hold. You can reduce the odds of fungal disease occurring in your garden by spacing plants out properly, pruning for good airflow, and keeping leaves dry. This means watering from below, rather than from above. Soaker hoses and furrow irrigation are better choices when fungi are present. (And they are always present.)
When fungal diseases strike, be sure to dispose of infected plant material in the trash, and sanitize garden tools between each cut.
I hope you now share my new-found respect for these amazing life forms.
Imagine an apple that tastes something like bell pepper.
That was the first description I could find for rose apples. I had never heard of these edibles until this morning when a friend told me she was having some problems growing hers in San Francisco. Let’s see what we can find out.
Rose apple family
Despite the name, rose apples are not in the rose family. Instead, they are a type of myrtle (Myrtaceae), making them cousins to cloves, guava, allspice, and eucalyptus.
Rose apples are native to Southeast Asia and the northern parts of Australia. These plants are tropical and cannot handle freezing temperatures. They thrive in moist heat with full sun. If any of these conditions is missing, trees will not produce fruit. They need to be irrigated in summer and kept on the dry side during periods of cold.
Mature trees tend to have a dense crown with many slender, arching branches that can make the tree wider than it is tall. Large, showy flowers appear in early summer.
The fruit is a slightly pear-shaped berry, with a hint of rose fragrance. The flesh is crisp and watery, with a taste that starts out mildly sweet and then turns to a floral rose or slightly bitter taste, depending on who you ask. These fruits are non-climacteric, which means they must be left on the tree until they are fully ripe before being harvested. Once picked, most varieties of rose apples do not ship or store well.
Like apples, rose apples often do not grow true from seed, although some people have had good luck that way. Very often, the fruit is substandard when started this way. Cuttings and most grafts generally fail, as well, so plants are most often reproduced vegetatively, using air layering.
There are four major types of rose apple, each with different characteristics. In many cases, there is an overlap of names, but it’s nothing to worry about unless you’re a botanist.
Jambos rose apples
Jambos rose apples (Syzgium jambos) feature yellow fruit with two seeds. They are also known as plum roses, wax apples, and pomarrosa. These trees grow 10-45’ tall and look very similar to guavas. Unlike guava fruit, which is filled with tiny seeds, these rose apples contain one or two large seeds. Apparently, when the fruit is ripe, you can shake it and hear the seeds rattle. Lance-shaped evergreen leaves and twigs are hairless (glabrous) and the brown bark is smooth. In temperate regions, these trees are self-fertile.
Java rose apple
Java rose apples (Syzgium samarangense) are also known as wax apples, wax jambu, and Java apples. These trees grow 40’ tall and have grayish-pink bark that flakes off. Leaves can be up to 10” long and 4” wide, and they smell nice when crushed. Java rose apples are bell-shaped and come in many different colors, with pale red being the most common.
Malay rose apples
Malay rose apples (Syzgium malaccense) are also known as mountain apples, Malay apples, pomerac, or simply rose apples. The oblong fruit of these plants is said to be refreshing but bland. Some varieties have pink or white skin, but most Malay rose apples have dark red skin and contain only one seed. Trees can grow 40-60’ tall.
Watery rose apples
Watery rose apples (Syzgium aqueum) are also known as water apples, bell fruit, and bush cherries. Water apples are true to their name in that they need lots of water, as in monsoon levels. The yellow fruit of water apples is described as the taste of apple and the texture of watermelon. Unlike other rose apples, this variety stores well. Glossy green leaves are also edible.
Rose apple problems
While rose apples have few insect pests, it ends up that they are fruit fly magnets. If you are growing rose apples, you need to harvest the fruit as soon as it is ripe. And discard overripe fruit right away. This will interrupt the lifecycle of the fruit flies, along with several other pests.
On the disease front, myrtle rust (Austropuccinia psidii), also known as guava rust, has all but wiped out the Hawaiian rose apple population. Since rose apples are introduced as ornamentals in many regions, this isn’t necessarily a bad thing. Unless it strikes your tree. Other common diseases and disorders of rose apples include anthracnose, leaf spot, mushroom root rot, root rot, and sooty mold.
All that being said, I think insufficient sunlight and cool temperatures are probably the problems being faced by my friend’s tree. [Sorry, Gaea!]
If you are growing rose apples, we’d love to hear about it in the comments!
Strange and exotic dragon fruit is even more bizarre when you learn that these delicious fruits grow on a vining cactus!
If you’ve never seen one, dragon fruits have bright pink, leathery skin and scaly spikes. The interior fruit is peppered with tiny black seeds, similar to kiwifruit.
White-fleshed dragon fruit (Hylocereus undatus) is the one we see most often in grocery stores. There are also red- and yellow-fleshed varieties, H. costaricensis and H. megalanthus, respectively.
Also known as pitahaya and strawberry pear, dragon fruit is probably native to Central America, though scientists are still debating over that.
The dragon fruit plant
Dragon fruit plants are climbing cacti with branches that put out aerial roots. Fragrant, edible flowers bloom at night. Pollination is usually done by bats and moths. These plants can handle temperatures over 100°F and light touches of frost. Too much time in freezing temperatures will kill a dragon fruit plant.
These plants can get big. Wait, let me say it another way – they can get HUGE! Multiple branching arms can grow 30’ long. That’s important information if you want to start growing your own dragon fruit.
How to grow dragon fruit
To begin, be sure to get a self-fertile variety. Also, having more than one plant will boost your harvest, if you have room. You can grow dragon fruit in 15-gallon pots to help keep it under control. This makes moving it to a protected spot in winter easier, too.
Being cacti, dragon fruit plants thrive in Hardiness Zones 10-11, though they can sometimes be grown outdoors in zones 9a or 9b. They grow best in slightly acidic soil with good drainage.
You can grow dragon fruit from seeds or cuttings. Like most cacti, broken-off bits of a stem will readily start producing roots when in contact with moist soil. [In some countries, dragon fruit plants are classified as invasive weeds.]
To grow dragon fruit from seed, be sure to remove all the fruit first and allow them to dry out. Then, lightly cover them with nutrient-rich potting soil and water regularly, allowing the soil to dry out slightly between waterings. Soggy soil usually kills seeds and seedlings. Seeds should germinate in a couple of weeks.
If you are growing a dragon fruit indoors, you will need to pollinate flowers by hand, which isn’t difficult. Dragon fruit plants usually reach full production when they are 5 years old and live for 20-30 years.
Dragon fruit problems
Most dragon fruit diseases are related to too much water. Overwatering and heavy rains can create conditions that allow several fungal and bacterial diseases to occur. Be on the lookout for anthracnose, black rot, blossom drop, brown spot, cactus stem rot, pitaya fruit rot, and white rot. This is why good drainage is so important. Also, you will need to monitor for aphids, mealybugs, mites, and thrips. These pests can suck the life out of your dragon fruit, and some of them may carry plant diseases.
If you’ve never eaten a dragon fruit, I urge you to try one. Then, decide for yourself if there’s room for this vining, fruiting cactus in your landscape!
A new weed has appeared in my lawn and it’s a member of the mallow family.
We’re not talking about roast-able marshmallows here, although it ends up there is an ancestral connection. Cousin to okra, hibiscus, cola nuts, and cocoa, the mallow family also includes cotton, hollyhocks, and linden trees. And an Old School ingredient of marshmallows. But we’ll have to get to that another day. Weeds move fast! I needed to stay focused before deciding what to do about this new weed.
Now, my Malva neglecta poses a problem for me. On the one hand, it is an invasive weed that attracts orange tortrix moths and weevils. On the other hand, it is an edible that clearly grows without any effort on my part. What’s a gardener to do?
I do what I always do - I learn more about it.
Here’s what I have learned about common mallow.
Common mallow plants
Common mallow is also known as buttonweed, cheeseplant (another great name!), roundleaf mallow, and dwarf mallow. This weed is native to Morocco, Mongolia, and Spain, just to name a few. In fact, this little weed really gets around!
Apparently, once common mallow appears, it can be hard to get rid of. [Uh, oh!] Tough, cheese wheel-shaped pods can hold and protect 10-12 seeds for decades. Once germination starts, a tough taproot stakes its claim, searching for hard-to-reach water and nutrients. Ultimately, plants can get 6-24” tall. I haven't seen any yet, but they produce pinkish-white flowers in mid-summer.
Common mallow plants can be annual or biennial plants, most often found in neglected areas. [I have to assume seeds blew in from my neighbor’s yard because there’s nothing neglected about my yard. Well, maybe a couple spots…]
An edible weed
The leaves, seeds, and stems of common mallow are edible. Mature seeds are cooked like rice, and immature seeds are eaten raw. I was surprised to learn that common mallow seeds contain 21% protein and 15.2% fat!
Traditionally, people have chewed the leaves to treat sore throats. Since most mallow family plants produce mucus, I suppose that it soothes irritation the same way apple pectin does. But I’m guessing. There are countless claims about common mallow as a medicinal plant, providing relief for everything from the common cold to childbirth difficulties. According to WebMD, there is currently no scientific evidence to back any medical claims made about common mallow.
So, the question is, should I pull them all up or let them grow?
As much as I love growing edibles, I think this one is going to have to go. First off, it is an invasive plant. Secondly, my husband really wants at least a little bit of green lawn in my backyard garden. Gotta keep the peace, right? There it is, the mallow goes. But that brings me to something else.
As you may have heard me say before, you can use the weeds in your yard to help you figure out which edibles should grow equally well. Since I know common mallows can grow well in my yard, maybe it’s time to try growing okra…
I’ve seen goji berries in seed catalogs, but haven’t (yet) tried my hand at growing them. This might be the year!
Also known as wolfberries, these bright reddish-orange berries are a type of boxthorn native to Asia. They have been part of Asian cuisine and medicine for over 2,000 years. Goji berries grow on somewhat thorny deciduous shrubs that produce numerous canes. In early summer, you’ll see small purple flowers. A month or so later, your crop will start to come in!
Pros and cons of goji berries
There are many claims about the health benefits of these members of the nightshade family. Said to help fight aging, diabetes, depression, high blood pressure, eye and skin problems, and more, these fruits contain high levels of Vitamin C, antioxidants, iron, and fiber. While research has backed some of those claims, it has shown negative interactions, as well. If you are taking warfarin, blood pressure drugs, or diabetes drugs, you may want to think twice about eating goji berries.
Another problem with goji berry products is that they have been found to contain high levels of pesticides and fungicides. If you really want goji berries, it’s probably a good idea to grow your own.
Goji berries have a very short shelf life, so growing your own is really the best way to go. As a bonus, the fruits don’t ripen all at once, so you can nibble a few berries as you putter in the garden. You know, the same way you might enjoy those delicious yellow cherry tomatoes that never seem to make it into the house.
Goji berry species
Before you start, you need to know that there are two different species of goji berry available. The fruits are very similar to each other, but Lycium barbarum and L. chinense taste slightly different from each other and they tolerate different temperature ranges. If you live in Hardiness Zones 3-10, you can grow your own Lycium barbarum goji berry bush. The L. chinense variety is said to have a more limited range, Zones 2-7, so be sure to get yours from a reputable seller.
Planting goji berries
You’ll need to give your goji berry plants some room. These shrubs can grow 10-13’ tall and 4’ wide, though they are often pruned to 3-6’ tall, for easier harvesting and management. They grow best in full sun, though they can tolerate partial shade. Goji berries prefer loose, somewhat alkaline soil, with a pH of 6.5-7.5.
Goji berry shrubs are most commonly grown from bare root stock. You can also start one from seed, but it will take a few years to get a crop and they don’t always grow true to the parent. Goji berries can be grown in large containers (at least 5 gallons), but they will be much happier in the ground because they have a taproot. Goji berry plants can be left as shrubs or trained up a trellis.
Goji berry care
The first year you have a goji berry plant, leave it alone except to water. Mulching around (but not touching) the stem can stabilize soil temperatures, retain moisture, and reduce weed competition. In the second year, allow a central cane to grow upright and prune all the others to a height of 15”. You may need to provide support to keep it growing straight up, much like when growing currants. As the plant gets taller, pinch back stems to promote lateral growth for better flowering and fruit production. The fruit is produced on new growth, so remove canes the winter after they produce fruit. This will make room for new growth and provide good airflow.
You can help your goji berry shrub live longer and be more productive by removing all the flower buds for the first couple of years. This will push the plant to develop a healthier root system. Your goji berry shrub will take 4-5 years to reach full production.
Goji berry problems
Like tomatoes, goji berries are susceptible to blossom end rot. Regular irrigation can help prevent that from happening. Common pests include aphids, birds, gall mites, Japanese beetles, leafhoppers, spider mites, and thrips. Diseases include anthracnose, early blight, and powdery mildew.
If you’ve ever grown goji berries, I’d love to hear about your experience in the Comments!
The fish tanks of our youth were often coated with algae.
As gardeners, you may see algae growing in planter pot saucers, rain barrels, or birdbaths. You may also see it growing on your soil.
But what do you really know about this plant family? And what does it do in your garden?
Algae are a large group of plants most commonly found in water. Most seaweeds are algae, but I doubt any of us are growing any seaweed in our gardens. Unlike moss, which prefers shaded areas, algae thrive in direct sunlight. Algae can also become a problem in greenhouses and on houseplants. By learning more about how these plants grow, we can find ways to reduce a few garden problems.
Algae are simple plants that contain chlorophyll and perform photosynthesis, the same as your tomato plants. Some of them absorb nutrients through osmosis, sucking, or surrounding and incorporating smaller life forms. Algae need water more than they need heat. This is why algae is often seen in spring and autumn on soil with drainage or overwatering problems. Algae do not have true stems, roots, leaves, or vascular tissues.
There are green, brown, red, and golden algae. There is also something called blue-green algae that is more closely related to bacteria than plants. These microorganisms are all believed to be some of the first lifeforms on Earth. But we probably don’t want them growing in our birdbaths or on our soil.
Algae on soil
A thin layer of green slime on exposed soil is usually algae. Algae won’t harm your plants directly, but it does compete for nutrients and water, and often attracts fungus gnats and shore flies. As the algae dry out, it can form a dark, dry crust that makes it difficult for water and gases to penetrate in either direction.
Algae prefer neutral to alkaline soil pH, so acidic soil is less likely to have a problem with algae. If your soil is heavy or compacted, adding compost can improve drainage. If you have an area that stays wet, you may want to consider installing a rain garden there. Rain gardens are sunken areas that put native plants to work to absorb excess water.
Algae in plant containers
Algae can grow on vermiculite, peat moss, and perlite, as well as soil. If plant containers and seedling pots are not allowed to dry out between waterings, algae spores floating in the air will take up residence. Rather than watering containerized plants from above, add water from below. This encourages the root system to expand downward and makes life more difficult for algae.
Algae in birdbaths
If your yard features a birdbath, keeping it clean is necessary for bird health. Red algae commonly grow in birdbaths and should be removed by scrubbing with a mixture of 9 parts water and 1 part vinegar. Birdbaths placed in sunny areas will have more of an algae problem than birdbaths placed in the shade. Position your birdbath accordingly.
If you see algae in your garden soil, try aerating the area. If you see algae in potted plants, let the soil dry out between waterings. If your birdbath is demanding more time than you want to give, move it to a shadier spot.
And if you haven’t seen the fish in your tank lately, it may be time for a good scrubbing,
If you grow beets or spinach, you should probably know about beet yellows virus (BYV) and beet pseudo yellows virus (BPYV). These two diseases look and behave enough alike that you really don’t need to know the difference, unless you start working in a plant disease lab. [I’d love to hear about that job!]
Along with BYV and BPYV, beet chlorosis virus and beet western yellow virus are two other diseases that can be included in this group for our purposes. [Unfortunately, I was unable to find a photo I could use. Do you have one?]
Symptoms of beet yellows viruses
Unlike the beet mosaic virus, where symptoms are first seen in new, younger leaves, symptoms of beet yellows viruses first appear on lower, older leaves. That yellowing is seen between the veins. If you look closely, you may also see reddish-brown spots. Those spots are like freckles, eventually becoming so numerous as to create bronzing. As the disease progresses, leaves thicken, becoming leathery and brittle. Of course, your beet plants can catch both diseases, or more, in a condition called virus decline, which can make diagnosis tricky.
These diseases are all spread by aphids. Aphids are bad. Aphids are the most common guilty parties when it comes to disease transmission. As they travel around your landscape, aphids pierce pretty much every plant they come across, looking for a tasty meal. Each time they do, viruses can move from the aphid to your plants. And beets aren’t the only plants that can become infected with beet yellows viruses.
Beet yellows viruses have can infect raspberries, strawberries, melons and squash, and members of the sunflower family. That’s probably half the edibles growing in your garden! Poppies can catch these diseases, too. So, what can you do about it?
Controlling beet yellows viruses
It only takes a single aphid to explode into a problem. They reproduce rapidly and don’t need help from another aphid to start making baby aphids. Beet yellows virus problems often begin in overwintered beets and other host plants. Cutting host plants off at soil level at the end of the growing season allows valuable soil microorganisms to migrate to other plants and you may even get new crops come spring! [I have found this is particularly true of cabbages, Brussels sprouts, broccoli, and Swiss chard.]
These tips can help reduce the risk of beet yellows viruses occurring in your garden:
Any time you start seeing leaf discoloration, take a closer look. It’s usually easier to control problems sooner rather than later.
Shoestrings are to be expected on your sneakers. Finding them in the garden is something else.
Leaves and stems grow in predictable ways, except that sometimes they don’t. Sometimes, stems grow strangely flattened. This is called fasciation. If you see leaves or other growths that look like a Halloween hag's broomstick, it's called witches broom. When leaves grow oddly thin and leathery, it is called shoestringing. There are several types of shoestringing and they have different causes and cures.
Temperature-based shoestringing is a disorder commonly seen on eggplant leaves. At first, you would see holes in the middle and on the edges of leaves. You might think it’s some sort of an insect, chewing on your eggplants. As the condition persists, you might suspect a viral disease, or maybe chemical overspray. In severe cases, you may see chlorosis or stunting. This type of shoestringing occurs most often when very warm temperatures happen at the same time plants are in very specific growth stages. In other words, there isn’t much you can do about it. You should still probably monitor for insect pests, just in case.
Chemical overspray can also cause shoestringing. This is most commonly seen when a neighbor sprays herbicide on a breezy day. Chemicals soar over the fence and land on your tomatoes or other crops, causing leaves to become thin and stringy. The same symptoms may also indicate viral disease.
If it wasn’t chemical overspray that caused shoestringing in your tomato plants, it might be cucumber mosaic virus (CMV). Are the leaves mottled? Take a closer look at the stems. If you see a zigzag pattern, it’s CMV.
Blueberry plants are susceptible to a virus that causes shoestringing. You won’t see any symptoms, at first. This disease lays dormant for up to 4 years before anything visible happens. Those symptoms include long red streaks on stems, most often on the side of the plant that gets the most sunlight. Leaves take on a reddish or purple straplike or cupped shape. Rather than deep purple, infected fruit has more of a reddish tinge. Normally white flowers have a pink tint. This disease is spread by blueberry aphids. Infected stems should be removed and the plant should be monitored closely.
Armillaria root rot is another viral shoestringing disease. Also known as shoestring rot, this disease affects several fruit and nut trees. Rather than growing normally, infected leaves cup downward and start yellowing. If you were to dig up the roots of a tree infected with Armillaria root rot, you would see blackened rhizomorphs, or shoestrings, growing on the surface of normal roots. In some cases, those shoestrings may grow upward, under the bark. And sometimes, they glow! Sadly, trees infected with Armillaria root rot need to be removed.
If you see shoestringing in your garden, look again. See if you can figure what's causing it. If you need help, just let me know!
Have you ever seen strange bits sticking out of your apple tree in spring?
Or, moths fluttering around your tree on a summer afternoon? You might want to take a closer look. Those bits may be discarded pupal casings from apple clearwing moths, and these pests can kill your tree.
Also known as red-belted moths, apple clearwing moths (Synanthedon myopaeformis) are native to Europe, North Africa, and the Near East. They were first seen in North America in 2005, in Canada. Now, Canadian entomologists estimate that the majority of host trees in British Columbia are infested. By 2007, these pests had made their way to Washington state. It’s only a matter of time until they spread further.
And apple trees aren’t the only ones vulnerable to this pest. If you grow almonds, apricots, cherries, crabapples, peaches, pears, plums, or quince, you should know about apple clearwing moths. These invasive pests also attack hawthorn and mountain ash trees and are attracted to showy milkweed plants.
Damage caused by apple clearwing moths
The moths themselves are harmless. It’s their larvae that cause significant damage, especially to older trees. Caterpillars burrow under the bark, entering at burr knots, grafts, pruning wounds, injured branch collars, and areas damaged by tree supports left in place for too long.
Larval feeding can kill young trees. Trees that survive often have weakened limbs, reduced fruit set, and early leaf drop. These conditions make trees susceptible to other pests and diseases and more vulnerable to drought stress and frost damage.
Apple clearwing moth lifecycle
These pests have a 2-year lifecycle. Female moths feed on nectar early to mid-summer, laying up to 250 eggs singly in crevices. When the eggs hatch, larvae burrow into the cambium layer. They feed on sap found in the phloem for the next two years. As they eat, they create shallow, winding galleries that weaken the tree. They also feed on new leaf and flower buds. In spring, you may be able to see the frass (bug poop) pushed out of these galleries by the larvae. [How about that? Even insects perform spring cleaning.]
Larvae spend the winter protected in these tunnels, pupating the next spring. When pupae are ready to break free and fly, they push themselves through these frass openings. In addition to these discarded pupal cases, you may also see tiny holes (about half the diameter of a pencil lead) around the base of an infested tree.
Apple clearwing moth description
It should come as no surprise that clearwing moths have transparent wings. Unlike most moths and butterflies, clearwing moths do not have scales on their wings. They do have short, bushy tails, though!
Apple clearwing moths have narrow, bluish-black bodies. Their forewings are slender and their hindwings are short. They have wingspans of ¾ - 1” wide and distinct reddish-orange bands around their bellies. Larvae are ½- ¾” long, a dirty white color with a reddish-brown head. Pupae are ½” long and pale yellowish-brown.
Apple clearwing moth control
Preventing this problem is much easier than fixing it. Start by making sure your pruning cuts are clean and flat and that they do not cut into the branch collar.
If you believe your trees have become infested with apple clearwing moths, do not use wires to probe the holes the way you might go after squash vine borers in your zucchini plants. Infested trees already have enough damaged areas. They don’t need more.
You may be able to reduce the number of adult moths emerging from cocoons by spraying Bacillus thuringiensis (Bt). Applications of cottonseed oil have also been shown to be helpful.
You can use the same yellow pheromone traps that attract male peach tree borers or make your own traps by baiting bottle traps with grape juice. To make a bottle trap, simply cut the top off a liter soda bottle and invert the top into the base. Tape the two parts together, creating a funnel. Male and female clearwing moths will be attracted to the grape juice but unable to find their way out of the trap. A mix of 8 parts water, 1 part apple juice, 1 part vinegar, and a little sugar has also been shown effective.
Just remember, if you put out attractants, whether food or pheromonal, you will be attracting moths to your garden. There are insecticides rated for use against apple clearwing moths, but they have their own drawbacks. Only do these things if you need to.
If you believe you have apple clearwing moths on your property, please contact your local County Extension Office right away. And try to capture a specimen.
If you have black mold in your house, you should go outside right away.
Garden variety black molds are something else entirely. Well, mostly.
Mold of any color
Molds are a type of fungus. Other common fungi include yeasts, mushrooms, and truffles. Fungi do not contain chlorophyll, so they do not perform photosynthesis. Instead, they get their food by breaking down and absorbing organic materials. Fungi reproduce using spores and many of them generate threadlike filaments, called hyphae. These hyphae develop into a complex network, called the mycelium. Despite all the similarities, slime molds, such as dog vomit slime mold, are not fungi. We’ll leave that discussion for another day.
You may see grey mold, white mold, black, or even blue mold. There are several different types of black mold. All of them produce black mycelium. Most of them are relatively benign, but some of them are dangerous.
Toxic black mold
After building materials are exposed to moisture from flooding or fire-fighting, Stachybotrys chartarum fungi start to grow. Generally rare in nature, these spores can also be found in grain and soil. Water-damaged buildings provide the perfect habitat for these microfungi to breed and grow. As they grow and are disturbed, they release toxins into the air that can make you sick. Toxic black mold needs to be removed right away.
Sooty mold is another black mold. Often seen on citrus and other tree leaves, onions and garlic, peanuts, and grapes, this black mold is the Aspergillus niger fungi. For the most part, this variety is safe to be around, unless you are a farmworker and exposed to it alot. In that case, a serious lung disease called aspergillosis can occur. This fungus can also cause fungal ear infections (otomycosis).
I was surprised to learn than the sooty mold fungus is commonly used in industrial applications to produce citric acid and high fructose corn syrup, and to clarify wine. Weird, right?
If you see sooty mold, apply sticky barriers to halt the protection provided by ants, and give your plants a wipe down to remove the mold.
Alternaria leaf spot
Also known as Alternaria rot and black rot, Alternaria leaf spot creates black or brown spots on the leaves of many garden plants. It can also create dark, round, flattened lesions on cherries, papaya, tomatoes, and many other fruits. Similar in appearance to blossom end rot, Alternaria leaf spot damage can appear anywhere on an infected fruit. [Unfortunately, I couldn’t find a photo I could use.] Exposure to the Alternaria alternata fungi has been found to trigger asthma and allergic rhinitis.
If this mold appears in your garden, your plants will benefit from proper spacing, pruning for better air circulation, and the removal of affected plant material.
Bottom line: If you see black mold, find out which type it is and take the appropriate action.
December is a time of skiing and sleigh rides in much of the northern hemisphere. Not so much in coastal California.
While iconic snowflakes rarely fall on my garden, your situation may be something else entirely. But, being from New England, I’ve seen my share. It wasn’t until very recently that I learned just how amazing each snow crystal really is.
Contrary to popular sentiment, bits of snow are not flakes. They are crystals. How these crystals form is mind-boggling. What it does to your garden may surprise you, too. But let’s start with a water molecule.
Most of us are familiar with H2O. That moniker tells us that each molecule of water is made up of two hydrogen atoms connected to one oxygen atom. It ends up that all those whirling electrons are pulled closer to the oxygen atom. This gives oxygen a slightly negative charge, leaving hydrogen atoms with a slightly positive charge. [Don’t run away! This will all make sense in just a moment.]
For snow crystals to form, water vapor, liquid water, and ice must all be present. As gazillions of water molecules float around in a cloud, their charges attract and repel each other like magnets. The negative side of a water molecule is pulled toward the positive side of other water molecules. [This is why water has surface tension, too.]
When snow crystals form, five more water molecules, in liquid form, collect on this negative side and end up creating a 4-sided pyramid, or tetrahedron.
As temperatures drop, this water turns to ice, suddenly shifting into the iconic 6-sided shape that decorates Christmas cards around the world. Up to this point, most snow crystals are identical. It’s when countless combinations of trajectory, humidity, and temperature changes are factored in that each snow crystal becomes unique.
[Did you know that snow crystals can form triangles, diamonds, and pillars? I didn’t either.]
Snow in the garden
If you wake one winter morning to see your garden blanketed in snow, don’t panic. While freezing temperatures can kill tender annuals, making a mess of leaves, a thick covering of snow protects plant roots, earthworms, and important soil microorganisms. Those chilling hours translate into bigger fruit and nut crops next year, too!
But how can snow crystals protect plants from freezing? It doesn’t make sense!
As temperatures drop, the water contained in plants expands as it freezes. This causes frost cracks in stems and blackened leaves. Snow-covered soil tends to stay right around 32°F. This happens because of tiny pockets of air caught within the 6-sided crystals. This air insulates whatever is covered. Of course, too much snow on tree branches can lead to breakage. You made need to prune or protect trees if you get a lot of the white stuff.
If temperatures happen to rise, well, plants get irrigated. Another surprising benefit is that nitrogen and sulfur in the atmosphere are captured as each crystal falls. When it melts, those important plant nutrients are released into the soil.
If snow falls on your garden this winter, take a cue from Nature and grab yourself a nice fuzzy blanket, a hot beverage, and start planning your spring garden!
You can grow a surprising amount of food in your own yard. Ask me how!
To help The Daily Garden grow, you may see affiliate ads sprouting up in various places. These are not weeds. Pluck one of these offers and, at no extra cost to you, I get a small commission that allows me to buy MORE SEEDS!