This pest is an outlaw, of sorts, carrying death and disease in its wake.
Glassy-winged sharpshooters may have a cool name (and they look pretty amazing), but they are a serious pest that carries several diseases to your garden and landscape plants. This pest first appeared in San Jose, California, in 2001 and efforts are being made to control its spread. Let's see how we can help control this pest.
Glassy-winged sharpshooter description
Sharpshooters are a type of leafhopper. They have narrow bodies and strong legs. Glassy-winged sharpshooters tend to be 1/2 inch long and dark, shiny brown above, and yellow underneath. The wings are clear with reddish veins and spines can be seen on the hind legs, if you look closely.
Glassy-winged sharpshooter lifecycle
Clusters of white eggs are laid on the underside of leaves and then covered with a white, powdery coating, called a brochosome. This coating and the nearby leaf tissue turn brown after the eggs hatch and the nymphs use their piercing mouth parts to suck sugary sap from the xylem. These nymphs will molt several times before reaching adulthood. While sharpshooter feeding is not a serious threat to healthy host plants, these insects carry many diseases, and their excrement forms a coating on leaves that looks like whitewash and falls on cars below. Heavy feeding on new, small plants can cause wilting.
Sharpshooter host plants
These pests are opportunists. Scientists estimate that there are over 700 different types of plants used by sharpshooters as food. These plants include grapes, citrus trees, and stone fruits. This means most of the fruit and nut trees in your garden or landscape are susceptible to these pests. What’s worse, as these pests feed, the bacteria they carry is injected into the plants!
Diseases carried by glassy-winged sharpshooters
The glassy-winged sharpshooter (Homalodisca vitripennis [formerly H. coagulata]), like other sharpshooters, are sap-sucking insects. As they feed on plants infected with the Xylella fastidiosa bacteria, the bacteria begin reproducing within the insects mouthparts. When the sharpshooter feeds on successive plants, the bacteria and the diseases they cause, are also transferred. These pests can bring several, currently incurable, diseases to your foodscape, including:
*These diseases have not yet been found in California, as of April 2018.
How to control glassy-winged sharpshooters
Insect predators, such as parasitic wasps, and naturally occurring pathogens are the most effective, long-term control measure, so avoid using broad-spectrum insecticides. In severe cases, insecticides may need to be used. Just be sure to use them sparingly and follow the directions exactly. Insecticidal soaps and oils have also proven effective.
If you see a glassy-winged sharpshooter, please contact your local Sheriff or County Extension Office right away!
[Yes, I’m kidding about the Sheriff. But I’m serious about the County Extension.]
You may see the word chelated [ˈkēlāted] on bags of fertilizer, but what does that mean, and how can it help (or harm) your garden?
Advertisers make many claims about chelated fertilizer. They say it will help your plants thrive and reduce chlorosis by making more soil nutrients available to plants. In some cases, chelates hold onto ions that pathogens need to growth, thereby reducing their population. These claims are all accurate, mostly.
What they don’t tell you is that the effectiveness of chelated products depends entirely on soil pH and that many chelated products are rather toxic to both the environment and to soil microorganisms. Before adding chelated fertilizers to your food crops, let’s find out what’s really going on, shall we?
The chemistry of chelation
Chelates (or ligands) are organic molecules (chemically speaking) that attach themselves to metal minerals found in the soil. The word ‘chelate’ comes from the Greek word for lobster’s claw (chelé). This word describes the claw-like mechanism that surrounds a metal nutrient and ‘complexes’ the mineral. This prevents the mineral from being oxidized or precipitated. Once a mineral is complexed, it is held until a root hair is reached. Then the mineral is released and absorbed by the root hair, and the chelate goes in search of another mineral. [Try wrapping your brain all of those actions taking place around the roots of all your plants… it’s mind boggling!]
Metal minerals as plant food
Metal micronutrients, such as copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), and zinc (Zn), are important food for your plants. But plants can only use these metals when they are in the form of water soluble ions. Very often, these molecules attach themselves to oxygen molecules and become oxidized, or hydroxide ions (OH-) to be precipitated. This makes them unavailable to plants. Both oxygen and hydroxide ions are abundant in the soil. When metal nutrient molecules become chelated, they can be absorbed and used by plants. In fact, plants produce some of their own chelates. This must mean chelation is a good thing, right? Well, not always.
The power of pH
If your soil has a pH greater than 6.5, as is common in the Bay Area, chelated fertilizer can provide plants with the nutrients they need in low quality soil without risking eutrophication. [Eutrophication refers to the condition of too many nutrients ending up in bodies of water due to urban drool and runoff, which leads to dense plant growth and animal death due to lack of oxygen. It’s not pretty.] Did you know that different minerals become unavailable at different soil pH levels?
No simple answers
Here is where I have my biggest concern about chelated products. All too often, people see plants not growing well, so they add fertilizer. The plants don’t improve fast enough, so more fertilizer is added. This cycle can continue indefinitely because the lack of all those nutrients isn’t the problem. Very often soil structure and soil health are the problem. It could be a lack of soil microorganisms, or the incorrect choice of plants for a certain microclimate. Frequently, the lack of a single nutrient, usually iron in the Bay Area, can make all the other nutrients unavailable. Without soil test results from a reputable, local lab, there is no way of knowing what your soil needs.
Before adding chelated fertilizers, you need to recognize that there’s much more to this situation than the Quick Fix claims. According to a report published by the University of Florida Extension Office, you need to take into account soil pH, your soil’s bicarbonate content, and the specific plant species when deciding whether or not to use chelated products. Bicarbonate levels? What does that mean? Bicarbonates are ions that precipitate (attach to) calcium, leaving salt behind. If your soil or irrigation water have a pH of 7.5 or higher, you can safely assume that the bicarbonate levels are higher than is good for your plants.
Are you sure you know what you’re doing? It’s not nearly as simple as advertisers make it out to be. [Is it ever?] And where do those chelates come from?
Chelated products normally include ingredients such as DTPA, EDDHA, and EDTA. Since iron is the most commonly chelated mineral, we will look at the effects of those ingredients on soil health and iron absorption:
Not all bad
There are times when the use of chelated fertilizers make sense, if used judiciously. For example, chelated iron helps you grow acid-loving plants, such as blueberries, in alkaline soil. Start by selecting the best form of chelate for your soil pH. You can avoid soil-based problems by using foliar (leaf) applications of chelated products, once you are certain of the need for them. You can also increase the number of naturally occurring chelates (and improve soil health) by adding more organic material in your soil. This is done by top dressing the soil with aged compost or mulching with clean wood chips.
Just remember, quick fixes that sound too good to be true are usually far more complex and risky than they are made out to be.
Almond trees are lovely in a landscape and they can produce up to 65 pounds of almonds a year. As far as fruit and nut trees go, almonds have shown themselves to this gardener to be trouble free, but problems can happen. One of those problems is called almond leaf scorch.
Almond leaf scorch is caused by the same bacteria (Xylella fastidiosa) that causes Pierce’s disease, in grapevines, and alfalfa dwarf disease. This disease can also infect many common weeds, including annual bluegrass, burclover, cheeseweed, chickweed, filaree, London rocket, and shepherd’s purse. This pathogen is found on many familiar plants, such as bermudagrass, blackberries, elderberries, fescue grasses, nettle, and rye, without causing any problems for the host plants.
How almond leaf scorch spreads
This disease is carried by sap-sucking insects, such as leafhoppers, sharpshooters, and spittlebugs. As they feed, the bacteria moves from the insect into the plant’s xylem, where it begins to reproduce.
Almond leaves are normally a lovely green color. Around June, however, you may notice the edges (margins) of leaves look scorched. If you look closely, you will see a yellow band between the scorched portion and healthy leaf tissue. This scorched appearance looks a lot like salt burn, but salt burn lacks the yellow band.
This disease is normally seen on one branch, or one scaffold of branches. Scaffolds are major horizontal branches. Over time, this disease spreads to the rest of the tree. Another name for almond leaf scorch is golden death. While infected trees can live for several years, they will leaf out later and be far less productive than a healthy tree.
Leaf scorch management
If your beloved almond tree becomes infected, early detection is critical. The infected branch, or its scaffold, should be removed 5 to 10 FEET below any visible symptoms. Keep a close watch to see if any signs of infection appear elsewhere on the tree. If the tree is less than 10 years old, your best bet is simply to replace the tree.
I hope that your almond tree never faces this problem, but now you know what to watch for.
The tiny Asian citrus psyllid is costing orange growers billions of dollars in losses, and it might be on your trees!
The Asian citrus psyllid (Diaphorina citri) arrived in North America from Asia or India in 1998. The insect feeds on the sap found in leaves and stems of citrus trees. As they feed, they produce large amounts of honeydew (sugary bug poop). This honeydew is a popular food of ants and the sooty mold fungus. That wouldn’t be a serious problem, by itself. The situation is made far worse because the Asian citrus psyllid carries a bacteria that causes a devastating disease called huanglongbing (HLB). Also known as citrus greening, HLB is a vascular disease that kills trees and there is no cure.
Trees infected with citrus greening must be destroyed.
Asian citrus psyllid identification
This pest is about the size of a grain of rice. It is a mottled brown color with a light brown head. The wings have a dark brown band around the outer edge and look as though they are being held up and behind the insect when at rest. Most adults have a dusty appearance. Nymphs are yellowish orange with long, white waxy secretions, called tubules. Tiny, almond-shaped eggs start out pale, turn yellow, and then orange just before hatching. [I couldn't find a photo I could use, so Google it.]
Asian citrus psyllid lifecycle
Adult females lay between 300 and 800 eggs. These eggs are laid on new growth, on shoot tips and between unfurling leaves. Nymphs go through five instars. The entire lifecycle takes from 15 to 47 days, depending on conditions. There can be up to 10 generations a year. [I don’t know about you, but that’s some crazy math. If there are any mathematicians reading this post, I would love to read in the comments just how many offspring that can mean!]
Host plants and signs of infestation
You can tell by the name that these pests feed on oranges, lemons, limes, and grapefruit. They have also been found feeding on kumquat (Fortunella sp.), Indian wood apple (Limonia polyandra), jasmine, citron (Citrus medica), pummelo (Citrus x maxima), mock orange, Cape chestnut, Bengal quince (Aegle marmelos), and others.
There are several signs of infestation that all citrus tree owners should watch for on a frequent basis:
Financial impact of Asian citrus psyllids
Some pests are more costly than others. This one tops the list. Infection of citrus trees around the world is wiping out entire regions of citrus growers. Companies that sell citrus products are paying more for domestic citrus, and they must also buy citrus products from other countries, causing the loss of local jobs. Also, over $1 million a year is being spent on public education, to slow the spread of this problem. This means even higher prices. The reason for this educational investment is that there are more citrus trees in backyards than in commercial orchards. Uninformed homeowners are far more likely to allow this pest to expand its range even further.
Halting the spread of citrus greening
Learning what to look for is one of the best ways to help slow this threat to citrus. These tips will go a long way toward preventing the spread of this disease:
Please read my post on huanglongbing disease and find out if you are in or near a quarantine zone. It is up to citrus tree growers everywhere to help combat this devastating pest.
If you suspect or see signs of the Asian citrus psyllid or huanglongbing disease, immediately contact the CALIFORNIA DEPARTMENT OF FOOD AND AGRICULTURE HOTLINE: 1‐800‐491‐1899, or your local Department of Agriculture.
Is it true that melons and squash can cross-pollinate? If I plant a lemon tree too close to an orange tree, will the oranges be sour? You’ve heard of cross-pollination, but what does it really mean and do you have to worry about it? Let’s start by reviewing pollination.
Pollination and fertilization
Pollination refers to the act of pollen, the male genetic information (gametophyte), moving from the anther to the (female) stigma. From there, the pollen grain grows a pollen tube, which makes its way down the style to the ovary. Two sperm cells (gametes) then move through this tube to fertilize female gametes. One male gamete fuses with a female gamete to produce an embryo, while the other fuses with a different type of cell, called a polar body, to form the endosperm, which will feed the developing embryo. [You can think of these two much like the yolk and white of an egg, respectively.] Since two fertilizations are actually occurring, it is called double-fertilization, but I digress.
Types of pollination
Pollination can occur one of two ways: self-pollination or cross-pollination. Self-pollinating flowers pollinate themselves. Cross-pollination, or allogamy, refers to the way pollen moves from one plant to another of the same species. Wind and insects, such as honey bees, are the main perpetrators of cross-pollination. Natural cross-pollination can only occur within a species (we will not discuss genetic manipulation at the nano surgery level).
To give you a clearer idea, consider this: Horses breed with horses. Donkeys breed with donkeys. When a female horse breeds with a male donkey, their offspring, a mule, is nearly always infertile. The same is true in the plant world.
This means that zucchini plants can cross-pollinate with pumpkins and other summer squash varieties, but not with melons or cucumbers. This is because squash and pumpkin are both members of the Cucurbita pepo species. In the same way, cucumbers (Cucumis sativus) cannot cross-pollinate with muskmelons (Cucumis melo). Their genetic information doesn’t match up properly.
When cross-pollination within a species does occur, the offspring (seeds) are often useless, but it has no affect on the current season’s fruit or vegetable. The only exception to that rule is sweet corn. When varieties of sweet corn cross-pollinate, the current season’s crop will exhibit characteristics of both species. In nearly all other cases, it is the DNA found in seeds that is altered. If you save seeds for next year’s crop (and I urge you to do so), you will grow plants with characteristics of both parent plants. This is how we get many new cultivars with desirable traits or unique properties. The only way to prevent cross-pollination is to keep crops 100 yards or more apart, which probably isn't realistic in your home garden. You can reduce the chance of cross-pollination by keeping plants as far away from each other as possible.
The science of genetics owes its start to cross-pollination among common pea plants
and a central European monk, named Gregor Mendel, back in the mid-1800’s.
Western tussock moth caterpillars can defoliate a tree in record time and they are wreaking havoc in many regions.
There are over 2,500 species of tussock moth (Lymantriinae) worldwide. The family name Lymantriinae comes to us from the Latin word for ‘defiler’. Cousin to the gypsy moth of East Coast nightmares. the western tussock moth is making itself felt west of the Rockies.
Western tussock moth caterpillars feed on leaves and young fruit. What makes these pests so much of a threat is how much and how fast they eat. Western tussock moth larva, or caterpillars, will feed heavily on apple, apricot, cherry, citrus, pistachio, plum, and prune trees, as well as many ornamentals, such as oak, ceanothus, and willow.
Western tussock moths (Orgyia vetusta, formally known as Hemerocampa vetusta) are normally present in this area, being native to the west coast of North America, but chilly winter weather and natural predators usually keep their numbers limited. Warmer winter weather allows these moths have a boom population, and 2018 is one of those years.
Currently, local parks and walking trails are finding trees, sidewalks, and park equipment covered with these caterpillars. Caterpillars are falling out of trees onto cars and people, there are so many of them. Newly hatched caterpillars have a habit of using a silk thread to balloon themselves to a new location. Walking into a cloud of ballooning caterpillars isn’t something most people enjoy.
Western tussock moth description
These pests are easy to identify. A Western tussock moth caterpillar is 1-1/2 to 2 inches long and features white tufts (called pencils) that stick up along the back, with two black tufts on its head, and one on its read end. They also have paler tufts along their entire length and sides. You will also see bright red and orange spots. The adult female moth is unique in that she does not fly. She is short-winged (brachypterous) and stays with the cocoon. She is a pale grey color, but you probably won’t see her. The males find her because of chemical scents, called pheromones, that she releases. The male moth does have wings. He also has prominent, fringed antennae. He may be dark or light brown, depending on the local environment, with black and white markings. Larva go through several stages, called instars. Until they reach their full size, they are black, with black hair pencils on their first four abdominal segments.
Western tussock moth lifecycle
Adult moths do not feed. Each female moth lays hundreds of eggs. Eggs are laid directly on the cocoon. The female moth covers the eggs with a protective coating and then covers that with a camouflaging layer of hairs (setae) from her own body. The eggs overwinter in this protected state and then hatch in spring through mid-summera. These caterpillars feed intensely for 40 to 60 days before pupating. While the caterpillars of some tussock moth species spread an irritant on the setae (hairs) that cover their bodies, the western tussock moth does not fall in that group, but they can be a pain, nonetheless.
Western tussock moth controls
Local governments use several methods to control heavy infestations of western tussock moth caterpillars:
Hopefully, your garden and landscape will be spared a visit from the western tussock moth. If you are not so lucky, you can spray Bacillus thuringiensis (Bt) to deter these pests. If a severe infestation does occur, you may have to prune out heavily affected limbs.
Most gardeners are familiar with monocots and dicots, but what are eudicots? Let’s find out!
Flowering plants (angiosperms) are often categorized by the type of seed they make. You can see these differences with the naked eye. Seeds that come in a single body, such as corn, are classified as monocotyledons, or monocots. Seeds that split into halves, such as peas and beans, have been called dicotyledons, or dicots. Cotyledons are seed leaves. They rarely look like the other leaves produced by a plant. Monocots generally have a single seed leaf, while dicots have two seed leaves. So, how do eudicots fit in?
High tech botany
Electron microscopes and genetic mapping are drastically changing the way we look at plants. Superficial similarities can no longer be used to classify them. In 1991, an evolutionary botanist, James A. Doyle, and a paleobotanist, Carol L. Hotton, created the term ‘eudicot’ to differentiate between simple, primitive dicots and more modern tricolpate dicots. [How’s that for a word?] Tricolpate is another word for eudicot. Molecular research demonstrated that dicots are not what we thought they were. In fact, dicots are not even included in the new taxonomy! This is because dicots are not all descended from a single ancestor.
[Did you know that the study of pollen grains and other spores is called palynology?
I didn’t, either.]
You will now begin hearing people talk about monocots, eudicots, and basal angiosperms. I would love to tell you that basal angiosperms are those primitive dicots, but it’s not that simple, either. For now, we will simply say that basal angiosperms are an “everything else” collection of flowering plants. If you want to get really technical, angiosperms are now divided into eight orders, instead of two, or three. Here’s the list and any examples I could find:
Eudicots are further separated into two groups: core eudicots and basal eudicots. Core eudicots include members of the sunflower family and the rose family. The basal eudicots are a more eclectic group. All this new information is being resorted using something called the APG IV system. We will discuss all of this in more detail another day. The reason behind much of this reclassification lies in pollen grain grooves.
Using an electron microscope, one can see that pollen grains have distinct patterns or grooves. Eudicots have three grooves, called colpi, that run parallel to the polar axis of the pollen grain. At the base of each of these colpi there are three or more openings, called germination pores. Most other seed-bearing plants, including gymnosperms and monocots, have only one germination pore. This pore is found in a groove called the sulcus. The sulcus is pointed in a different direction from the more visible grooves.
Using these new classification tools, we learn that eudicots make up 75% of all flowering plants and 50% of all plant species. At this point, that means there are over 280,000 eudicot species on Earth! Those species include apples, cannabis, figs, olives, oranges, peaches, peas, and plums, along with oaks, maples, and many others.
So, the next time someone starts talking about monocots and dicots, you can set them straight with the latest botanical discoveries!
Most of us grew up learning about how pollen sticks to bees as they go from flower to flower, collecting nectar and pollinating many common food crops. But that’s not how it works for your tomatoes and peppers. Instead, they use buzz pollination.
Most flowering plants (angiosperms) have male parts, called anthers, that have pollen on the outside, available to all takers. This pollen held in place by its extreme stickiness. [That stickiness is why you need to use soap and water to get pollen off your face and eyelashes, for those of you who are prone to allergies.] This pollen can be knocked loose by busy pollinators and then carried on the wind, or the pollinators find themselves covered with the sticky stuff, as they move from flower to flower, feeding on nectar and collecting pollen.
Dry, dusty pollen
Some flowers don’t have sticky pollen. Instead, they have pollen that is dry and dusty. If that pollen was exposed, it would all be gone with the first breeze, most of it never making it to another flower. Instead, these plants have evolved a specialized type of anther, known as a poricidal anther. Poricidal anthers are tubes with tiny openings at one end, but these openings are too small for bees to use. To make matters worse, these plants generally do not offer nectar, so how do they get pollinated?
Pollination by vibration
Approximately 8% of the world’s flowers are only pollinated when the correct sound wave frequency occurs nearby. When it does, the flower explodes a small dose of pollen into the air, coating whatever is at hand with genetic information and protein-rich food. This is called buzz pollination, or sonication. It gets those names because certain insects that have learned how to buzz at just the right frequency to trigger these plants to share their bounty.
These flowers release pollen at frequencies between 40 to 1000 Hz, depending on the species [You can use a tuning fork or an electric toothbrush to try this for yourself.] Scientists believe this arrangement evolved as a means to ensure that each visiting pollinator carries away a smaller portion of pollen (which they are less likely to drop on their way to the next flower) and that those portions are spread out over a greater number of pollinators, and over a wider time frame, for better odds of procreation. How’s that for evolution?
Not honey bees
Honey bees do not use sonication to get at pollen, but several other bees do. Sweat bees, carpenter bees, and bumblebees all use buzz pollination to get at the pollen held in poricidal anthers. They do this by disconnecting their wings from their flight muscles [I have no idea how they do this!] and vibrating those muscles at just the right frequency. In most cases, this frequency is close to middle C. The force generated during sonication can reach 30 Gs, which is almost more than a human can tolerate!
Which plants use sonication?
You may be surprised to learn that many common garden plants use sonication. Members of the legume and nightshade plant families frequently use buzz pollination to generate the fruits and vegetables we love. In addition to tomatoes and peppers, other edible plants that use buzz pollination include eggplants, potatoes, peas, blueberries, tomatillos, and kiwifruit.
How are your flowers being pollinated?
Antlions are fierce predators of the garden.
Cousin to lacewings and owlflies, and often mistaken for dragonflies or damselflies, these beneficial insects fly at dusk and at night. It is their larvae, however, that do the most damage to garden pests, such as ants and termites.
Adult antlions live for only 20 to 25 days, and most antlion species do not eat anything. Those that do only eat pollen and nectar. Instead of dining, they flutter around at dusk and during the night, attracted to lights and flames, in search of a mate. After mating, the female lays her eggs in sand or plant debris. Those eggs hatch into ferocious larvae that feed until they are ready to pupate into adults. This entire cycle make take 2 to 3 years to complete.
Adult antlions have two pairs of clear, thin wings, and a narrow abdomen. They can be differentiated from damselflies by their long, clubbed antennae. Also, adult antlions don’t appear to fly very well.
Antlion larvae are often called doodlebugs because of the squiggly trails they leave behind. Antlion larvae are spindle-shaped, with a plump middle and three pairs of legs. [You may have seen a variation of an antlion in the ‘Ceti eels’ from Star Trek II: Wrath of Khan]. Antlions appear to have a mobile neck (prothorax) and the head is flattened with very large, heavily ‘toothed’ jaws. Those teeth are actually sharp, hollow tubes. Within these jaws of death, antlion larvae have a canal that carries venom to immobilize their prey and enzymes to liquify them, once they are paralyzed. If that weren’t terrifying enough, antlion larvae feature forward facing bristles that help them to stand stand ground against significantly larger prey. One weird thing about antlion larvae is that they do not have an anus. Instead of releasing waste, they store it for later use as a building material for their cocoon. Any unused waste material is then released at the end of its pupal stage. [I suppose that it’s no surprise that antlion cocoons look like rabbit droppings or bird poop…]
Signs of antlion habitation
How would you know if antlions are in your garden? You might see adult antlions fluttering around your porch light. Or, you might see holes in the ground. While some antlions hide in wait for their prey under leaf litter, other species of antlion larvae trap their prey in pits. They build these traps by walking backwards in circles, flipping grains of dirt and sand out of the hole with its very large jaws. Ultimately, they end up with a very steep-sided hole that can be 3/4” to 1-1/2” deep. The soil or sand around the pit is loose. At the bottom of that pit, the antlion larvae waits quietly for its next meal. As an unsuspecting insect walks by, they may fall in. When they do, it’s all over for them! As soon as prey fall in, the antlion quickly flips more soil out of the hole, making it deeper and causing grains of soil to fall on the prey, knocking it deeper into the hole. Finally, the insect is grabbed by the antlion’s large jaws and the liquefaction of its insides begins. After everything has been sucked out, the husk it thrown out of the hole and everything is tidied up for the antlion's next guest.
There is a tale that says you can talk antlion larvae out of their holes. Simply bend down, close to the hole, and tell the antlion to tell you what you want to know. At the sound of your voice, the antlion emerges from their hole, but why? The tale says that the larvae want to hear what you have to say. What’s really happening, is the soil is disturbed by your movement and the sound vibrations of your voice, so the antlion thinks it either has lunch, or a housekeeping job to attend to.
There are over 600 antlion species worldwide. Antlion larvae are often used as fishing bait, and some people keep them as curiosity pets. How many do you have in your garden?
Oats in the garden or landscape? Why not?
Long, long ago, when people were first growing cereal grains in the Fertile Crescent, there was a weed on the side of the fields. These weeds may have benefited from the irrigation and fertilizers used on the primary crop, or they may have cross-pollinated - I don’t know. But that pesky weed turned out to be oats, of oatmeal cookie fame.
Oats are members of the grain plant family (Poaceae). Like other cereal grains, the seeds we use to make oatmeal are actually a fruit, called a caryopsis. Unlike other grains, oats contain a legume-like protein, and eating oats regularly can help reduce cholesterol levels. Along with alfalfa, wheat, ryegrass, clover, and timothy, oat hay is grown as animal fodder. Even today, oats (Avena sativa) are grown more as livestock fodder than for human consumption. [My chickens LOVE oat seed heads and leaves.] But, there are plenty of other reasons to grow this versatile weed-come-cereal-grain.
Oats in the landscape
Oats make an attractive stand of tall stalks and waving seed heads. As an annual, oats can reseed an area. Unlike many other grain crops, oats are not as attractive to most small songbirds. Larger birds, such as mourning doves, may flock to your oat stands. I think that their pretty cooing often makes up for any lost grain. But why would you want to add oats to your landscape or garden? Here are just a few good reasons:
How to grow oats
You can plant oats as soon as temperatures are consistently above 40°F. Seeds can be broadcast over an area and raked in or, in the case of severely compacted soil, a drill can be used to create holes 1/2 to 1 inch deep. How much seed was a little tricky to calculate for the home garden. All I could find was information for farmers, which told me 2.75 to 3.25 bushels per acre. Huh. I own a bushel basket but I have never had a bushel basket full of seeds. Ever. After hunting around on the internet, I have come to the conclusion that you should simply follow the directions on the seed packet. If you want to see what I learned, you can read the note below.]
Oats grow quickly. Also, oat plants are triggered to flower as nights get shorter, in a behavior called photoperiodism, so seeds become available rather quickly. Oats are heavy feeders, so side dressing young plants will give them the nutritional boost they need to thrive.
Oats are more tolerant of cooler temperatures and rain than other cereal grains, which makes them a good late winter and early spring crop, here in the Bay Area. Most oat plants will go dormant in the high heat of summer. The stems and stalks left behind by your oats are called stover. Stover can be added to the compost pile, used to create barriers, or left in place for climbing beans to use as a trellis.
The oats you see growing along roadsides are probably wild oats (Avena fatua). Many farmers are angry about wild oats because of cross-pollination.
Oats and crop rotation
In traditional crop rotation, a three-field system would grow legumes in one field, a grain, such as oats, in a second field, and allow the third field to rest, or go fallow. You can use a similar plan, whether you grow in rows, raised beds, or containers. This practice interrupts the disease triangle of many common plant pathogens.
Pests and diseases of oats
Bacterial blights can affect oats, along with stem and bulb nematodes, and barley root knot nematodes, dried fruit beetles, and crane fly larvae. Fungal diseases, such as leaf blotch, stem rust, crown rust, and powdery mildew are common, but not serious, threats for the home garden.
You may never harvest your oats, but, then again, you may. If you harvest these tiny fruits while they are still green, you can eat them fresh from the stalk (they don’t taste like much), or you can wait until they ripen and get hard. When I say hard, I mean it. These little suckers are like tiny oval rocks. Guess what? That’s why oats are rolled. Rolling oats means they are crushed between two giant heavy rollers, to flatten them and make the fruit accessible. Honestly, unless you are growing acres of oats, it probably isn’t worth trying to make your own oatmeal (even though you can).
Grown for their attractive, soil improving, chicken feeding properties is reason enough for adding these members of the cereal grain family to your annual crop rotation, garden, or landscape.
Seed calculation Rabbit Hole:
In the world of plants, crown can mean two very different things.
Like the fancy hat on a monarch’s head, crown can refer to the canopy of a tree. It can also mean the part of a plant slightly above and below the soil line. In both cases, the more you know about them, the better your plants will grow.
Tree top crown
Technically, the crown of a plant refers to everything that is above ground. Most people, however, use the term to describe the outer branches or canopy of a tree. In either case, mature crown size is an important factor when selecting a site for a tree. While most trees don’t mind mingling their branches, there are a few species that exhibit ‘crown shyness’ and will grow in such a way as to keep their distance from the branches of other trees. Tree crowns are classified by their shape. They can be rounded, weeping, funnel-shaped, spreading, pyramidical, oval, or conical.
Leaves that make up the crown are responsible for far more than just photosynthesis. In addition to being the major food manufacturing system of the tree, they also filter out dust and other particles from the air, slow the speed at which raindrops hit the ground, and shade the ground below the tree, stabilizing soil temperatures for the root system. [Seven or eight trees also produce the oxygen you need to breath each year.]
Tree crowns can be reduced moderately using heading cuts. Pruning in this way can lead to increased stem development lower in the tree, which means even more pruning to maintain air flow and sun exposure, while limiting the fruit load to a level that the tree can safely support.
In most cases, these diseases can be prevented with simple cultural practices:
Exceptions to the rule
In some cases, transplants can be replanted deeply enough that the lowest set of leaves end up underground. These leaves should be removed at transplanting time. The nodes where the leaves were are then transformed into root tissue, increasing the availability of water and nutrients found in the soil. This practice is not recommended for most plants. However, tomatoes and peppers, in particular, can increase their yields substantially with this practice. I have heard mention of using the same technique on brassicas, such as cabbage and broccoli, but I could not find any verifiable proof, so I am skeptical until proven otherwise.
As you walk through your garden, be sure to inspect the ground level crowns of your plants for signs of fungal disease and pests. Then, look skyward for a quick check on the overall form of your trees. These quick checks can reduce your workload and protect your plants over the long haul.
How can a clover be a weed? Is it all bad? Let’s find out!
California burclover (Medicago polymorpha) is an invasive annual weed that looks a lot like other clovers. The name polymorpha refers to the fact that the burrs can be smooth or snaggish. As far as weeds go, this one isn’t entirely bad. Also known as burr medic, bur trefoil, and creeping burr, this weed actually has a lot going for it.
Cousin to white clover, black medic, and strawberry clover, California burclover is sometimes grown on purpose to feed livestock. Being an annual, however, it will leave bare patches in your lawn, come summer. Also, those little burrs can wad themselves up on your favorite sweater and they are not particularly fun to step on barefooted. While some burrs are smooth, most of them feature rows of tiny velcro-like hooks that snag. Like other weeds, the best time to pull them out is when they are small and young, before they go to seed.
California burclover identification
Seed leaves (cotyledons) are oblong. The first set of true leaves are rounded. Mature burclover leaves look like they fold in the middle and are three round leaflets. They may have reddish midveins and toothed margins. Stems can reach 2 feet long and tend to trail, but may be upright, and they break easily. Small yellow flowers form in clusters at the end of stems. The seed pod is either smooth or a prickly burr that sticks to pet paws and fur, shoes, clothes, and enough other things that this pesky weed can easily be brought into your garden or landscape after a stroll around the block. These burrs look as though they are twisted on themselves. They start out green and then turn brown and hard. While these prickly burrs can get tangled in your pet’s fur, they are not the “stinging” “life threatening” weeds sensationalist articles claim. We will leave those claims to the foxtails.
The good side of burclover
In addition to being grown as livestock and chicken food, California burclover is also used as a ground cover, winter erosion control, green manure, and in soil restoration. A drought tolerant legume that thrives on slightly alkaline soil, burclover requires very little water and it grows rapidly into a dense vegetative cover that adds nitrogen to the soil. A single acre of burclover can produce 8300 lbs. of biomass in a single season! In many areas of the world, burclover is rotated in pastures with cereal grains for a continuous supply of healthy food for livestock. If you were/are a farmer growing hay for livestock, adding burclover to your oats and wheat can increase production by 3 to 5 times.
But you probably see burclover as a weed in your lawn, as I do. Now that I know burclover is also a nutritious legume, I will feel better about feeding those weeds to my chickens.
Dust. We see it every day. But what’s in it, and what does it do to your plants?
We’ve all heard the claims of houseplants removing toxins from indoor air, but what about the plants themselves? What does all that toxic dust do to them?
Indoor dust is generally made up of dead skin cells (dander), upholstery and carpet fibers, paper, and hair, but it also contains flame retardants, cleaning product particles, and chemicals from electronic equipment, insulation, sheet rock, paint, and flooring materials. Many of these chemicals are already known to be associated with cancer, reproductive problems, and hormone disruption in humans. They can also harm your plants.
Along with soil, animal matter, and minerals, most outdoor dust particles today also contain car fumes, plastic particles, aerosols, emissions from mining and other industrial processes, salts from eroded soils, and chemicals from nearby farms or landscapes. Wind that blows over coal-fired power plants, petroleum plants, steel mills, and mining sites carries toxic dust with it. Dust particles can also increase erosion, adding a sandpaper effect to every breeze.
In one case, the dust from California cement factories blew against nearby hillsides,
sickening or killing entire stands of California sagebrush (Artemisia californica), brittle brush (Encelia farinosa), white sage (Salvia apiana), and black sage (Salvia mellifera). These plants were critical to local birds, animals, and insects. The dust also altered the chemical makeup of the soil.
Dust as pollution
Dust is one of the most common forms of air pollution. In 2008, it was estimated that 30 million tons of dust are kicked up into the atmosphere each year. Because of urban development and global industrialization, the amount of dust in the atmosphere is increasing each year.
While 35,000 people die in car accidents each year,
it is estimated that 53,000 Americans lose their lives to car emissions
Many of these people live near freeways or other high traffic areas.
What does that say about the dust particles faced by your plants?
What does dust do to plants?
As dust falls on a leaf, the leaf is smothered. If the leaf’s surface was wet, the dust turns into a mud that collects even more dust and then dries to form a hard barrier. The amount of dust on a plant is called its dust load.
Very small dust particles can often be absorbed by plants. When this dust is simply pulverized soil or other naturally occurring materials, this isn’t a problem. Plants have evolved to handle these materials (up to a point). When this dust includes toxic chemicals, it can cause a host of other problems. Dust covered leaves also make it harder for trees to reflect sunlight, increasing the plant’s temperature. This makes them more susceptible to water stress and other negative effects of drought. Dust can have both physical and chemical effects on your plants. As dust is absorbed, it can alter cell wall exchange sites, interfering with nutrient uptake. Dust affects plants negatively in many other ways:
This means there is less energy, less water uptake, reduced gas exchange, and smaller crops. But things get worse, depending on what makes up that dust.
Pathogens cause disease. They can be bacteria, viruses, or fungi. Many pathogens blow in on the wind, and become part of your plants’ dust load. These pathogens can cause diseases such as fireblight, cankers, powdery mildew, eutypa dieback, rust, spotted tomato wilt, cucumber mosaic and many others. [Of course, Mycobacterium vaccae is also part of that dust load - these are the microorganisms that help you feel happy!]
Indoors and out, mites and mealybugs love dust. Whiteflies also have the advantage when your plants are dusty. Outdoors, mites, especially spider mites, thrive in areas with lots of dust. The dust mites in your home are a common cause of allergies and other respiratory problems. [Actually, it’s mite poop that causes the reaction…]
Reducing dust load
You can help your plants (and your family) thrive by reducing the amount of dust they have to deal with. There are several ways to reduce dust load:
Your plants and your lungs will thank you!
Under the bark of your fruit trees, there may be tiny bark beetles, chewing destructive tunnels.
There are over 200 different types of bark beetles in California (600 nationwide). We currently host 20 invasive species of bark beetle, half of which were only discovered since 2002. The shot hole (or shothole) borer has been here long enough that it is considered naturalized.
Bark beetle galleries
Bark beetles spend most of their lives in a system of tunnels, called a gallery. They chew these tunnels under the bark, in the sapwood or cambium layer. If you pull the bark away from an infested area, the gallery can clearly be seen. As the larvae feed on sapwood, expanding the gallery, these tunnels criss-cross each other, damaging the xylem and phloem, making it difficult for trees to transport water and nutrients. Parent tunnels tend to be 2 inches long and run parallel to the grain. They are normally clean. Larval tunnels, like a teenage boy’s room, radiate away from the parent tunnels, against the grain, are smaller, and tend to be filled with frass and sawdust.
Shot hole borer host plants
Shot hole borers, also called fruit tree bark beetles, prefer (you guessed it!) fruit trees, especially those in the stone fruit family. This means your almond, apricot, cherry, nectarine, and peach trees are susceptible, along with apple, pear, and avocado. Shot hole borers also feed on English laurel, mountain ash, hawthorn, and elm.
Shot hole borer lifecycle and feeding
Shot hole borers (Scolytus rugulosus) start out as white, round or oval eggs, laid in the gallery. These eggs hatch out into white, legless larvae that are 1/6 of an inch long and slightly larger just behind the head. These larvae overwinter in the gallery, creating more tunnels. As they feed, they poop. To make room for this material, the borers widen their tunnels and push the poop out, leaving signs of frass and sap to drip down the side of your tree. All this chewing causes further damage to the tree’s vascular bundles.
After 6 to 8 weeks of tunneling and pooping in your fruit tree, the larvae are ready to enter a pupal stage. Pupae are white, with tiny hairs and large knobs (tubercles). Pupae are found at the end of tunnels. Finally, adult shot hole borers emerge to chew exit holes and the cycle starts all over again. Adult shot hole borers are only 1/10” long and brown or black.
These new adults first emerge in spring or early summer and will feed on small twigs, buds, and leaf bases before chewing a new entry hole, where they will excavate more tunnels, further weakening your trees. Entry holes are often found near lenticels. Lenticels are lens-shaped openings in the bark used in gas exchange (sort of like a breathing hole, but not really). Female shot hole borers lay up to 50 eggs. There can be 2 or more generations each year.
Symptoms of shot hole borer infestation
As shot hole borers first start chewing galleries under the bark of your fruit trees, you are unlikely to see their entry holes (unless your vision is a lot better than mine). These holes are only 3/100 of an inch in diameter. What you may see, however, is oozing, gumming, or staining, as the tree tries to defend itself. You may also see crusty white exudates. [An exudate is something that seeps out.] This white crust is sugar from the tree’s sap. You may also see a sawdust-like frass. If you look very closely, you may be able to see a female’s abdomen sticking out from the hole. Twig dieback may also be seen. Much like the shotgun pattern seen on leaves infected with the shot hole disease fungus, shot hole borers leave behind a similar pattern on tree bark, hence the name.
Shot hole borer controls
Healthy trees are generally able to protect themselves against shot hole borers. This means regular irrigation to avoid water stress, proper fertilizing, depending on the age, size, and life stage of the tree, and pruning out dead and diseased wood. It also mean whitewashing trees in late winter to prevent sunburn damage to the bark. If infested wood is found, it should be removed and destroyed, to prevent the borers from spreading to healthy wood. Once shot hole borers are in the wood, there isn’t much else you can do. Insecticides are ineffective. You may be able to thwart some borers by applying sticky barriers around the trunks of your trees.
Bottom line: keeping your trees healthy in the first place is a lot easier than pruning out branches and twigs infested with shot hole borers!
Peppermint candy, peppermint tea, peppermint oil, and peppermint bark are all great reasons for growing your own peppermint.
Like other mints, peppermint (Mentha x piperita) is easy to grow. It tends to spread, so you can let it run wild as a fragrant ground cover, or rein it in as a container plant. However you grow it, peppermint is sure to add a delightful fragrance and flavor to your foodscape! Just be sure you understand how tenacious this plant is - it is considered an invasive plant in many parts of the world.
The mint family
The mint family (Lamiaceae) has grown alongside humanity since prehistory. It is a huge family that includes basil, oregano, thyme, rosemary, sage, marjoram, bee balm, lemon balm, lavender, savory, and many others. Mints are perennial plants that spread using rhizomes. Mint leaves have glands that produce aromatic oils. This is why they smell so lovely. Most mint plants have square stems. Flowers grow on spikes, and are generally a lovely blue or purple. If you look closely, you will see that mint flowers have four stamens and five fused petals, with two petals pointing up and three petals pointing down. Mints can tolerate drought and poor soil, making them an excellent choice for difficult areas.
The peppermint plant
Peppermint is a hybrid between spearmint (Mentha spicata) and water mint (M. aquatica). Water mint thrives in acidic wetland areas of Europe, western Asia, and northern Africa, and is now naturalized around the world. Traditionally used in South Africa to treat depression, water mint has been found to contain naringenin, an MAO inhibitor. Spearmint, of chewing gum fame, got its name because of its pointed leaf tips. The volatile oils and menthol of spearmint have made it a popular addition to toothpaste and baked goods. It can also be used as an insecticide against moths. Spearmint prefers partial shade, but can be grown in full sun to nearly full shade. [Did I mention how rugged mint plants are?] Because peppermint is a hybrid, it does not produce seeds and can only be propagated vegetatively.
Peppermint leaves are dark green with reddish veins, and they contain more menthol than spearmint. Peppermint has a fibrous root system. There are several different peppermint cultivars to choose from. My favorite is ‘Chocolate Mint.’ If you chew a leaf, fresh from the plant, you’d swear you were eating a peppermint patty! And no calories! Other peppermint cultivars include:
How peppermint grows
Peppermint loves lots of sunlight, but can also be grown in partial shade. Peppermint will grow 12 to 36 inches tall, but it can also be mowed regularly to keep it short. [And it smells amazing when you do!]. Peppermint is easy to grow from cuttings, simply make sure there is a node somewhere on the stem, cover it with soil and keep it moist until new growth emerges. Then allow the soil to dry out between waterings. Because of its preference for moisture, peppermint and other mints will need to be irrigated regularly during our California summers. As rugged as this plant is, once it becomes established, it is pretty difficult to kill. They may start slowly, but then there’s no stopping them!
Peppermint pests and diseases
The same volatile oils that give peppermint it’s refreshing flavor also work to deter many common pests, including mosquitoes! Mint root borers and webspinning spider mites are the most common mint pests in San Jose, California. Nematodes, cutworms, aphids, and grasshoppers may all take a bite out of your peppermint plants, but these pests are not normally much of a problem. Also, beneficial insects, such as the spider mite predator (Neoseiulus fallacis) will fight off more common pests without any effort on your part. All you have to do is avoid using broad spectrum pesticides.
Young peppermint plants grow slowly, so competition from weeds can be a problem. Also, some fungal diseases, such as verticillium wilt, anthracnose, and leaf spot diseases may occur, especially on older plants.
Harvesting and using peppermint
You can snip off fresh stems or leaves anytime for immediate use. For drying or distillation, leaves and flowers can be harvested as soon as flowers begin to open. Peppermint’s cooling properties have made it popular topical treatment for muscle pain, tension headaches, and itching. There is even research that demonstrates peppermint is able to provide some relief for irritable bowel syndrome. The aroma of peppermint has also been shown to improve memory and alertness! This is a truly useful plant that takes little care.
Too much peppermint can cause skin irritation or heartburn, but you’d have to use an awful lot of it. Also, some people are allergic to peppermint, but it’s rare. If you take medications for heart conditions, high blood pressure, or to decrease stomach acid, you should use peppermint with caution. [Did you know that peppermint is used in plumbing and construction to help locate leaks? I didn’t either.]
You can beat the summer heat with a spray bottle filled with water and just a few drops of peppermint oil. [It’s easy to make your own peppermint oil. Simply fill a container with a light oil - I use extra virgin olive oil - and a bunch of peppermint leaves. Cover and allow it to sit for a few days. Strain out all the solids and that's it! You have your very own peppermint oil!]
If you ever eat too much, nothing helps ease discomfort faster than a cup of strong peppermint tea.
Find a place in your foodscape for peppermint today!
Zinc may help you prevent or reduce the effects of a bad cold, but your plants need it, too!
Zinc (Zn) is a heavy metal micronutrient. It is called a micronutrient because only a tiny bit is needed. The recommended soil levels of zinc range from 1.0 to 7.6 parts per million (ppm). For comparison, a macronutrient, such as calcium, has a recommended range of 1000 to 1500 ppm. But don’t let the small numbers fool you!
How do plants use zinc?
Plants use zinc to break down carbohydrates and to regulate sugar consumption. You can think of it as a plant’s insulin. Zinc also activates certain enzymes. In a study by Juliane Clause, et al, we learn that zinc is moved around in a plant, partly through transpiration, and that zinc is used to facilitate dozens of important chemical reactions within a plant. That study also state that plants use zinc to counteract oxidative stress and as intercellular messengers! Some food plants, such as dandelion, contain a lot of zinc. Other plants, such as avocado, need a lot of zinc. Zinc is commonly applied to grapes, but only before the vines bloom.
Unlike many other plant nutrients, which are freely absorbed in solution, zinc is only available to plants in a positively charged form (Zn2+) that must be carried in on specialized transporter proteins. Zinc, on its own, cannot cross cell membranes. Once a plant absorbs a zinc molecule, it is mostly immobile. This means that signs of zinc deficiency usually show up on newer growth.
Symptoms of zinc deficiency
Zinc deficiencies are very rare, east of the Rocky Mountains. Alkaline soil and too much phosphorus, such as we have in the Bay Area, can make it difficult for your plants to absorb zinc and copper. Zinc deficiencies are more commonly seen in containerized plants. Symptoms of zinc deficiency include bronzing, twig dieback, and chlorosis. That chlorosis often presents as yellowing between young leaf veins and general bleaching that does not reach leaf edges (margins) or midribs. The bleaching may also look like yellow or white stripes between the veins of upper (newer) leaves. Zinc deficient leaves may also roll or curl, and may be smaller than normal.
Copper deficiencies look very much the same, to the untrained eye, so the only way to really know what is wrong is to submit a soil test to a local, reputable lab for analysis. [If you thought your DNA report was fascinating, you’re going to love reading your soil test results!]
Too much zinc
Just as too much phosphorus can make iron and copper unreachable for your plants, too much zinc can bind with iron, making nearly all the other nutrients unavailable. Signs of zinc toxicity, no surprise, look identical to iron deficiency. Zinc toxicity is normally seen in areas with widespread mining or industry and is characterized by severely stunted growth, transplant failure, and wilting. Dark blotches may be seen on older leaves and red areas on vines, petioles, and along margins (edges) and veins.
Before adding fertilizer, you really need to have your soil tested. And those cute little over-the-counter kits are not able to give you the information you need.
Zinc sulfate is a compound used by commercial almond growers in autumn to force trees to drop all of their leaves. These leaves are then collected and destroyed. This is done to reduce the chance of bacterial spot on almonds. This is not something for home orchardists to use without training.
Preventing zinc problems
Soils with insufficient organic matter are more likely to have nutrient imbalances. This means heavy clay soil, improper soil pH, too much calcium carbonate, and poor soil structure can all contribute to zinc and other plant nutrient problems. The best way to prevent or counteract these problems is to develop healthy soil by composting, mulching, and sprinkling some coffee grounds around.
Research is showing us that malnourished soil results in foods with lowered nutrient values. When you start talking about feeding 7 billion people, that can be a real problem.
Feed the soil in your garden and landscape properly, so that it can feed you!
Scapes are long, leafless flowering stems that grow out of a bulb or other underground structure.
Scape or stem?
Many people generalize that a scape is a flower stem, but it is not that simple. Botanically, a scape is a single internode, without leaves or branches, that either provides the base for, or becomes, the flower stem, or peduncle, and that it arises directly from an underground structure, such as a bulb, corm, or root. Most flower stems tend to emerge from twigs or spurs, instead.
Which plants have scapes?
In the world of edible gardening and foodscaping, scapes are the flowering stems of chives, garlic, onions, leeks, and scallions. The scapes of these edible plants can be eaten. The flavor becomes stronger and the scape becomes tougher as it matures, so scapes are normally harvested while still young and tender. Cyclamen, tulips, amaryllis, day lilies, and many succulents also feature a scape.
Pleaching? What on earth is pleaching and how is it related to gardening? Let’s find out!
Pleaching, also called plashing, is an age old method of keeping livestock in and wildlife out of the garden. This is done by weaving dead twigs and branches in among the living branches of a hedge to create a fence or wall. It is also done by partially cutting and then bending living branches. According to Julius Caesar, Gallic tribes used pleaching as an effective barrier against cavalry. Over time, pleaching evolved into an art form known as tree shaping.
Since medieval times, gardeners have protected their crops and their livestock by planting fast growing trees or hedge plants, or pleaches, in a line, relatively close to one another. Then, as branches developed, they would weave those branches together with those of neighboring trees. Any gaps or weak spots would be filled in with dead branches to form a convincing barrier. Very often, branches would be cut part way through, using a tool called a billhook, and pulled down into a more horizontal position. Because the vascular bundle was still partially intact, water and nutrients could still be brought up from the soil. Pulling these branches into a horizontal position also stimulated what were the lateral branches into growing vertically, filling in the hedge.
Thieves and livestock are far less likely to push their way through a fence made of thorny plants. Because of this, brambles, such as blackberries, were and are used in the same way. Traditionally, living bramble canes would be cut in half, bent over and woven together. As the canes quickly repaired themselves, they created a dense, prickly barrier that few thieves or predators would care to cross.
Because of the way trees grow, these branches would, eventually, merge and become one. This is called inosculation. It is a form of naturally occurring graft. This is a variation on free-standing espalier.
Nothing says summer like a sweet, juicy, sun-warmed nectarine. The good news is, you can probably grow a nectarine tree in your yard, along a fence, or even in a large container.
Nectarines are delicious fresh, stewed, baked, and sautéed. They freeze well and make excellent jam. Nectarines (and peaches) are so useful and tasty, that they have been cultivated for thousands of years. First grown in China, nectarines and peaches have been around for 2.6 million years!
What’s the difference between nectarines and peaches?
Fur. The only difference between a nectarine and a peach is a single gene that produces fuzzy skin (dominant) or smooth skin (recessive). A nectarine (Prunus persica var. nucipersica or var. nectarina) is simply a peach without the furry skin (trichomes). Nectarines and peaches are both members of the rose family, along with apples, pears, blackberries, raspberries, and strawberries. Nectarines and peaches, like apricots, cherries, plums, and almonds, are stone fruits. There are both cling and freestone varieties, and you can find yellow and white peaches and nectarines. [Yellow fruits are more acidic than white fruits.] Peaches and nectarines are also in a group of plants that use specialized cells for storage, manufacturing, and as weapons. These cells are called idioblasts. Don’t worry, though, they can’t hurt you.
The main reason you do not see nectarines in the store year round is because they do not ship and store well. While nectarines are usually smaller, firmer, and more aromatic than peaches, they also bruise more easily. [All the more reason to grow your own!] A standard nectarine tree can reach over 30 feet in height, semi-dwarf varieties reach 12 to 15 feet tall and wide, while dwarf nectarine trees are only 8 to 10 feet and they can be pruned for an even smaller size while still producing a good crop. Nectarines can also be espaliered, if you only have a narrow space along a wall or fence.
Each spring, your nectarine tree will produce lovely pink blossoms, followed by a delicious crop of fruit, and then all the leaves fall off (making dormant pruning so much easier!). Before you jump on the nectarine bandwagon, however, that yummy fruit can only occur if enough chill hours are accumulated each winter.
Nectarines and chill hours
Chill hours are an accumulation of temperatures between 32°F and 45°F. Somehow, trees keep track of this information. I have no idea how. If enough chill hours are not accumulated, nectarine flowers and buds will not form properly, which means you might not get any fruit. Different nectarine varieties have different chill hour requirements, so it is important that you select a variety appropriate to your location. Do not trust your local box store to sell you the right one. Most nectarine trees need 650 to 850 chill hours. Here in the Bay Area, we only get 450 chill hours (or 52 chill portions). You can learn your own chill hours on my chilling hours page.
Nectarine site selection
Once you have found a variety that matches your garden’s chill hours and your personal tastes, you will want to select a site with excellent drainage and plenty of sunshine. Also, nectarines prefer a soil pH of 6.5. Here, in the Bay Area, our soil is more alkaline than that, so acidification may be needed for the best results. Nectarines, like peaches, are self-fruiting, so you do not need multiple trees for pollination. While you may be tempted to grow a nectarine tree from a pit, think twice about that. Most commercially grown nectarines are actually from two different trees: a root stock and a fruit producing tree. These two trees are grafted together to take advantage of the benefits provided by a strong root system and good fruit production. Your store bought nectarine pit may never produce fruit at all. Or it might. You are far better off buying bare root stock from a reputable producer. Nectarine trees can also be started from twig cuttings called scions.
How to plant a nectarine tree
Bare root trees are best planted in winter and early spring. Examine the root system for signs of disease or damage. These bits should be cut out. If your bare root tree is not going to be planted right away, it should be soaked in a bucket of water for 6 to 12 hours, but no longer. [Plants can drown, too, you know!] When you are ready to plant, dig a hole that allows the roots to spread out freely. If the soil is heavy clay, be sure to rough up the edges of the planting hole. Containerized and balled trees should be given a hole slightly larger and the same depth as the container or root ball. In any case, it is very important that the soil level remains the same. Add soil around the roots and water thoroughly. This removes air pockets that can dry roots out before they ever get a chance to grow. Mulch around your new tree and water regularly until the root system has become established. The first 2 or 3 years, flowers should be removed, to encourage a strong root system. I know it’s hard, but you’ll thank me later.
Feeding and watering nectarines
Nectarine trees use a lot more nitrogen than other fruit and nut trees. You can use blood meal, ammonium sulfate, or commercial 10-10-10 fertilizer to feed your nectarine tree. Young trees will need a total of 10 to 15 lbs. of manure or 1/4 lb. of urea, spread out over the months of spring and summer. Mature trees should receive twice that amount. If your nectarine tree doesn’t get enough nitrogen, you will start seeing red areas on the leaves.
Nectarines are shallow-rooted trees, so they are susceptible to water stress during the summer. You can protect your tree with deep irrigation and a thick layer of mulch, just make sure that the mulch does not actually touch the tree trunk. If your nectarine tree becomes too water stressed, it will develop a condition called bitter fruit which is exactly how it sounds. The problem is, once bitter fruit occurs, the tree will forever after produce fruit that is bitter. If you keep your nectarine tree properly irrigated throughout the growing season, you can improve the taste and sweetness of the fruit with deficit irrigation, just before harvest.
Another technique used to improve both the quantity and quality of fruit is called cincturing, or scaffold girdling. This is not the same thing as girdling your nectarine tree with the weedwacker. Get help from an experienced arborist, rather than trying this on your own, as it can kill your nectarine tree.
Nectarine pruning and thinning
Nectarine trees perform best when they are trained in what’s called an open center system. This is exactly what it sounds like. Each winter, you will want to remove 50% of the previous year’s new growth. This will stimulate fruit production and maintain a reasonable tree size. One problem that commonly occurs with nectarines and peaches is that trees produce more fruit than they can support. This can mean broken branches. Proper pruning and fruit thinning can save your tree. Thin fruits to 6 inches apart when they are the size of a marble. If you think there is too much fruit on a branch, you can always prop it up with a board or other support until after the fruit is harvested, and then prune and thin more heavily next year.
Nectarine pests and diseases
The most common diseases faced by nectarine trees here, in San Jose, California, are peach leaf curl and brown rot. Nectarine are also susceptible to crown gall, bacterial blight, citrus blast, bacterial spot, stem blight, and shot hole disease.
Peach twig borers are a common pest of nectarines. Peach twig borer infestations often appear as dead twigs, called flags or shoot strikes. Luckily, many beneficial insects, such as braconid wasps, mealybug destroyers, and tachinid flies love to eat peach twig borers, so avoid using broad spectrum pesticides. Armyworms, earwigs, eugenia psyllid, Japanese beetles, mealybugs, San Jose scale, green fruit beetles, Mediterranean fruit fly, armored scale, eriophyid mites, katydids, and birds are also common pests. [Who can blame them?] You can use tree cages to protect your crop from birds in summer. Kaolin clay can be applied to individual fruits to protect against some pests.
In fall, after harvesting your delicious crop and before the first heavy rain, apply fixed copper to control shot hole fungus, fertilize plants one last time, and give your tree a deep watering. After all the leaves fall, move them away from your nectarine tree. Destroy or compost the leaves to prevent the spread of apple scab. As always, remove mummies as soon as they are seen.
Bordeaux mixture, dormant oil sprays, and fixed copper sprays should be used in fall and winter to protect against San Jose scale, shot hole disease, and other fungal diseases. You can prevent brown rot with a spring fungicide application. Crawling pests can be blocking from reaching fruit by wrapping the tree trunk with a sticky barrier.
Nectarines are ready for harvest when they come away from the tree easily with a gentle twisting motion. The fruit will bruise easily, so be gentle when handling ripe nectarines.
If you install a nectarine tree this spring, you can expect to have a tree for 7 to 20 years, depending on where you live. Since each nectarine tree can produce up to 65 lbs. of fruit each year, or approximately 200 nectarines, you will have plenty of delicious fruit to go along with a lovely tree.
Plant one today!
You can grow fruit and nut trees in surprisingly small areas using a method called espalier.
Espaliered trees are trained to grow in a two dimensional form, usually along a fence or wall, on a trellis, or between support wires.
We get the word espalier from the Italian word spalliera, which means ‘something to rest your shoulder against.’ This was back when the word referred to the structural framework used to support the initial growth of the tree. Now, we say that a tree trained in this way has been espaliered.
Put simply, a tree is espaliered by cutting it back to a specific height, usually 18 inches, and then retaining only two or three buds. As these buds grow out into branches, they are trained along a trellis, fence, or support wires, while still flexible. As these branches mature, they become rigid. Buds on these branches are selected for the next level of growth and all other buds are rubbed off. Over time, a simple or complex structure can emerge that takes up very little space, but that can produce a surprising amount of food.
Benefits of espalier tree training
Tree training, in general, provides several benefits to the trees and to homeowners. Dead, diseased, and crossed branches are removed, the tree is opened up for better air circulation and sun exposure, and the likelihood of broken branches due to an overly heavy crop is reduced with proper tree care. Espalier training takes it a step further by controlling the size and location of where a fruit or nut tree can be grown successfully.
A mature standard sized fruit tree can get quite large. Standard apple trees are 30’ across and 30’ tall, semi-dwarfs reach 20’ high and 20’ across, and even dwarf trees will grow to 15’ tall and 15’ wide unless they are pruned for size. Many homeowners simply do not have that kind of space available. This is where espalier training is particularly useful. In addition to keeping trees healthy, espaliered trees offer additional benefits:
How to espalier a tree
The first step in espaliering a young tree, shrub, or woody vine, is to transplant it 6 to 12 inches from a wall, fence, or trellis. This spacing is important for air flow and pest control. You can then install eye bolts into masonry joints, galvanized eye screws into a wooden fence, or build a trellis to support and train your tree. Starting while the tree is small, prune it to create a central stem (trunk). As branches emerge, only paired horizontal branches are retained. All other new buds are pruned away or rubbed off. These paired branches are trained to grow along the same horizontal plane, normally along an support wire or wooden framework. Grapes have been grown in this way for thousands of years.
There are several variations on the espalier theme:
Which trees can be espaliered?
There are many different edible trees, shrubs, and woody vines that be trained into an espalier. These plants include almond, apple, Asian pears, crabapple, citrus, fig, loquat, nectarine, olive, peach, pear, and plum. Many different ornamental plants, such as yew, privet, magnolia, winter jasmine, and camellia can also be espaliered.
Espaliered trees can be used as hedges, walls, or yard art. With skill and patience, free-standing espaliered trees can create a big impact.
You can grow a surprising amount of food in your own yard. Ask me how!
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