Since people first started growing plants for food, we have been battling the pests that eat, damage, or infect those plants.
Initially, those battles were hand-to-hand combat. Pests were removed by hand, chased away, and puzzled over. Then came the age of ‘better living through chemistry’, when powerful concoctions were sprayed willy-nilly, threatening entire species. Now, the pendulum has swung in a new, more balanced direction. That direction is called integrated pest management.
Integrated pest management (IPM) is a program of science-based pest controls with the minimal disruption of natural cycles and least harm to other organisms. Integrated pest management was made a national policy in the U.S. by President Nixon in 1972.
What are pests?
Your younger brother or sister may have been a pest when you were kids, but garden pests never outgrow the potential to cause damage. Garden pests include any organism that can harm or hinder the plants we want to grow. Using this definition, a pest can be disease-carrying bacteria, viruses, or fungi, a plant-eating insect or animal, a competitive weed, destructive soil nematodes, or a neighbor’s cat that thinks your carrot patch is its litter box.
What is IPM?
IPM takes a long view on reducing the negative impact of pests in ways that are sustainable and responsible. An integrated pest management plan has six basic tenets:
Rather than relying on a single method of control, IPM combines these tenets, in the order presented, to reduce the negative impacts associated with killing off pretty much anything. Rather than spraying chemical pesticides and insecticides on your food plants and into the soil and water table, you can work your way through these sustainable practices for surprisingly effective control of most garden pests.
Monitoring for pests
The first step in an IPM program is monitoring. Monitoring involves more than simply looking for bugs. Monitoring for problems begins by arming yourself with factual information about your soil and microclimate. This means sending out a sample for a soil test. Test results will let you know which nutrients are at acceptable, toxic, of deficient levels, along with soil pH, soil organic matter levels, and base saturations. It also means noting sun and wind exposure levels at various locations in your yard, the likelihood of frost damage, drainage problems, and preexisting pest problems. Each of these conditions play powerful roles in keeping plants healthy enough to defend themselves against pests.
After collecting all that information, go outside and start look for pests. You don’t know what you are up against without looking. You can use pheromone traps and yellow sticky sheets to help collect information of what costs are present. As you see pests, learn to identify them and then read up on them. Learn enough about them to counteract the damage they do without causing undo damage of your own. This is where things like trap crops come in handy.
The next step is to decide just how much damage you are comfortable with. Wiping out entire species is generally not a good plan. Evolution takes time and the balances that are created can be delicate and easily thrown out of whack. Allowing tolerable levels of pests to be present provides food for beneficial insects which will help you fight the battle against those and others pests.
Cultural practices are the way you manage your garden. Do you use overhead watering, which can encourage fungal disease, or do you use soaker hoses? Pruning for proper air flow and good structure go a long way toward pest control. There are several good cultural practices that help your plants stay healthy:
The third plan of action is mechanical controls. Row covers, tree cages, tomato cages, netting, sticky barriers, brassica collars, mulch, shade cloth, tree supports, trellising, and fencing are common mechanical controls that help plants stay healthy. This stage of pest control also includes trapping, hand picking, and soil solarization. Cold frames, greenhouses, and hoophouses also provide mechanical controls that reduce pest damage by making life harder for the pests.
There is an army of beneficial insects ready to help you control pests naturally, if you will only get out of their way. Instead of using chemical pesticides and insecticides, which can kill off beneficial predators and parasites, install insectary plants and provide water to create a welcome habitat for the natural enemies of the pests in your landscape.
Other biological controls include the release of sterile insects (generally performed by government agencies and universities) and introducing other natural predators periodically. Unfortunately, buying ladybugs and other predators rarely works as well as you might hope. They generally don’t stick around. Creating a welcoming environment is far more effective.
Chemical pesticides are used as a last resort. Pesticides should be selected as appropriate for the specific pest being controlled and used in ways to avoid affecting non target organisms.
Whichever chemical controls you use, it is important to switch things up periodically to prevent the likelihood of pest resistance. Pest resistance occurs when an organism develops an immunity toward a treatment, making it necessary to use ever-stronger poisons against them. Insects and pathogens evolve much faster than we do, so there is a limit to what we can tolerate.
Finally, after monitoring the situation and deciding which pests can be tolerated, using good cultural, mechanical, biological controls, and applying only necessary chemical controls, be sure to assess the situation, to make sure the problem is being corrected. If it isn’t, you need to go back and learn more about the pest(s) causing the problem to develop a new plan of action.
Generally speaking, pests appear seasonally and on specific crops. Knowing when to look and where to look can give you a jump-start on controlling the pests that damage your garden plants.
You can help the scientific community by participating in citizen science projects, such s the Big Bug Hunt, where you report insect sightings as you see them. This helps researchers develop better predictions about when pests are likely to appear in your area.
Trichogramma wasps are small but mighty
These microscopic parasitic wasps protect an astounding collection of edible plants. It might be easier to list those they do not protect, but your almond, apple, avocado, beet, blackberry, blueberry, celery, cherry, corn, cotton, grape, orange and other citrus, legume, papaya, peach, peanut, pear, plum, pumpkin, quince, squash, strawberry, tomato, walnut, and zucchini plants and trees are better off when Trichogramma wasps are in the neighborhood. These tiny wasps protect your plants from damage by parasitizing the eggs of these garden pests:
Parasitic wasps lay their eggs in many common garden pests. This group of beneficial wasps includes braconids, chalcids, Goniozus wasps, ichneumon wasps, and Trichogramma wasps.
Female Trichogramma wasps seek out the eggs of pesky moths and butterflies and sawflies to use as nurseries for her own eggs. When she finds one, the first thing she does is drum on it with her antennae and ovipositor to see if it has already been used. Drumming also helps her determine how big and useful the host egg is. This dictates how many eggs she will insert.
After being inserted into a host egg, the wasp egg develops, pupates, and then hatches, after which it feeds on the contents of the host egg. This turns the host black. If you use a hand lens and see a healthy white host egg with a chewed hole, it means the egg was not parasitized and a healthy (destructive) caterpillar emerged instead.
Trichogramma wasp species
Unless you are a scientist with a very powerful microscope, you will never see a Trichogramma wasp. At 1/25“ to 1/50” long, you could fit 20 to 40 of them nose-to-tail across a dime. If you could see them, you might be struck by the simple beauty of a minuscule yellow wasp with red eyes. Or, you might not. There are over 200 species of Trichogramma around the world.
Before you order a shipment of Trichogramma wasps as a biocontrol, keep in mind that different species of Trichogramma parasitize different hosts. It is important that you order from a reputable seller to avoid releasing a threat to other beneficial insects into your garden. When reading product descriptions, take the time to do a little research before you buy.
Trichogramma wasp eggs are shipped as larvae in host eggs that have been glued to cards. If you buy Trichogramma wasps for release, these tips will give them the best chance at being successful:
Keep in mind that Trichogramma wasps will not kill all the pests they come across. What they do is provide one piece of an integrated pest management program that uses natural processes to reduce the overall impact of pests, rather than spraying chemical poisons on your food.
Watch out for the yellow jackets and hornets, leave mud daubers and paper wasps to go about their business, and add some insectary plants to attract and provide for beneficial wasps, such as the Trichogramma.
Goniozus wasps can sting, but you’ll never have to worry about that.
Like many other parasitic wasps, adult Goniozus wasps mostly feed on nectar, sap, and other sweets. The benefit they provide is that they also parasitize pests of almond, apple, citrus, fig, pistachio, walnut, and coconut trees, as well as blueberries, blackberries, grapes, and strawberries.
Navel orangeworm, obliquebanded leafroller, and light brown apple moth caterpillars are favorite egg-laying hosts, giving Goniozus the common name of navel orangeworm wasp. Personally, I prefer Goniozus - in my mind, it’s the Gonzo wasp. These garden helpers also use banana scab moths and several insect pests associated with galls as hosts.
Goniozus wasp description
There are 20 different Goniozus wasp species, and they all look like tiny flying ants. Walking through the garden, you may simply see a very small, shiny brown or black wasp-waisted insect. Most insects who fit that description are beneficial, so resist the urge to swat them away. Instead, take a moment and see if you can tell what they are up to.
Similar to cuckoo bird species, which lay their eggs in the nests of other birds, Goniozus wasps are also known as cuckoo wasps because they lay their eggs in the bodies of other insects.
Adult females use their stinging ovipositor (egg-laying tube) to paralyze their victims, injecting hosts repeatedly with venom. The venom of some Goniozus wasps is permanent, but not all. In those cases, the venom only lasts half an hour or so, so she has that much time to transport her victim, mostly by dragging the much larger host, to a good hiding spot. If necessary, she will continue to inject venom over several hours, if that’s how long it takes to get where she needs to go.
Once tucked safely into a crevice somewhere, some females will feed on the juices of said caterpillar over the next few days, aiding in the development of her eggs. This does not always kill the host. In some cases, the host simply walks away, a little worse for the wear, until the eggs hatch and begin feeding from the inside out.
Goniozus larvae go through several developmental stages over the next 2 or 3 days, attached to their host, ultimately spinning tiny cocoons around themselves before reaching adulthood. Apparently, Goniozus wasps have been observed paralyzing far more hosts than they can possibly use for egg-laying. No one knows why.
How to attract Goniozus wasps
Beneficial parasitic wasps can be attracted to your garden with insectary plants. Insectary plants provide the food and shelter needed by these garden helpers. Most insectary plants feature umbrella-shaped flowers commonly seen in carrot, dill, cumin, mint, and cilantro, or globe-shaped flowers, such as chives. Allowing these plants to go to seed not only attracts beneficial insects, but seeds then create perpetual, edible crops. Other insectary plants include cosmos, sweet alyssum, yarrow, dandelions, and borage.
Adding these useful plants to your yard looks nice, too!
Unlike beneficial parasitic wasps, hornets attack honey bees, steal honey, invade bat houses, girdle branches, and ruin summer picnics.
So why would we want to tolerate hornets in the garden? What good can they do? Let’s find out!
Worldwide, there are 22 hornet (Vespa) species, including:
There are also 3 species of nocturnal Asian Provespa, which are not actually hornets.
Despite their name, bald-faced hornets (Dolichovespula maculata), commonly seen in California, are not true hornets, either.
There is only one true hornet found in North America: the European hornet (Vespa crabro). Introduced in the 1800s, this hornet is now found throughout the U.S.
Hornets are highly social insects. They live in large colonies, housed in papery hives, that are commonly built in dark crevices, such as dead tree trunks, under house eaves, and in your garage. Hives are made up of interconnected brood cells. Both the queen and workers can lay eggs. Fertilized eggs laid by the queen develop into sterile females, called ‘gynes’ while eggs produced by workers develop into males, called drones. Drones mate with the queen during ‘nuptial flights’. As a result, a hornet’s nest is largely populated by two nearly distinct gender-dictated populations. Workers care for the eggs as they move through larval and pupal stages, ultimately emerging as adult hornets.
Hornets and yellow jackets are both types of wasps, though yellow jackets tend to be smaller, with more yellow and black, while hornets tend toward more black and white or yellow and brown coloration.
Most hornets average 3/4” to 1”, while queens can be 1-1/2” long. If you look closely, you might be able to see that a male hornet abdomen has six segments, while females have seven segments and a stinging ovipositor.
Hornet stings and allergies
Like many other stinging insects, hornets become aggressive when they feel accosted (swung at, stepped on, sat on, that sort of thing), or when they believe their food supply or the colony are threatened.
Hornet stings are more dangerous to humans that other insect stings because they contain higher concentrations of acetylcholine. Hornet stingers are not barbed and can be reused many times. Also, when one hornet stings you, it releases chemicals that tell other hornets to sting you, as well. These same chemicals are also released when you kill a hornet or spray a hornet’s nest with poison, so be forewarned.
If you are allergic to stinging insects, you should always carry antihistamines or an EpiPen with you. Signs of an allergic reaction include shortness of breath, swelling of the face, lips, or throat, severe itching, weak or racing pulse, nausea, wheezing or gasping. If any of these symptoms occur, get medical help immediately. Call 911, grab a family member, or a neighbor right away. These symptoms can quickly escalate into a life-threatening situation. Otherwise, follow these steps to ease your temporary pain:
You can also take aspirin or acetaminophen to ease the pain, just be cautious about mixing medications, as that can cause yet another medical problem. Generally speaking, you are going to feel really miserable for 30 to 45 minutes, moderately uncomfortable for the rest of the afternoon, and you may experience discomfort for a week or so. You may also want to apply hydrocortisone or calamine lotion to the area. Pastes made of baking soda or colloidal oatmeal can also sooth the area. If you haven’t had a tetanus shot in the past 10 years, that can be a good idea, as well.
So, why would we want hornets in the garden?
Adult hornets feed on sweets, such as fallen fruit, sap, and your lemonade. They also collect insects for their larvae. This is part of the reason why they cause us so much grief during picnic season. From a hornet’s point of view, it is simply defending a food source when it refuses to back down from your burger and fruit punch. In addition to your picnic, European hornets commonly chew up beetles, dragonflies, grasshoppers and crickets, katydids, locusts, mantises, moths, and other wasps. This pulp is then taken back to the colony, where it is fed to larvae in the nest.
If you start having a hornet problem while dining outside, you can reduce the chance of stings by placing a plate of meat and fruit somewhat away from the picnic table.
If hornets become a problem around your home, try excluding them before poisoning them. Those chemicals tend to create more problems than they resolve.
There is far more to wasps and hornets than you might expect.
This group of insects is massive and it contains many beneficial insects. You may not be familiar with chalcidoid wasps, but odds are pretty high they’ve been working hard in your garden all along.
The chalcidoid superfamily of wasps contains 22,500 known species, with an estimated 500,000 species yet to be named. One of those families in particular, the Chalcididae, gives us chalcid wasps. And figs.
Chalcid wasp description
Ranging from only 1.5 to 0.75 mm (1/50 - 1/100”), you could fit 12 to 24 chalcid wasps nose-to-tail across a dime, so you probably will never see one. If you could see them, you would understand how they got their name. The word ‘chalcid’ comes to us from the Greek word for ‘copper’ because most chalcid wasps are a metallic bronze or copper color, though some species are metallic blue or green, and some are the more classic black and yellow variety.
Beneficial chalcid wasps
Most chalcids are parasitic wasps. They lay their eggs in several common garden pests. When the eggs hatch, larvae feed on the host insect before pupating into adult wasps. [I know, it’s sounds awful.] Those hosts include the eggs and larvae of flies, beetles, moths and butterflies, some spiders and nematodes, and true bugs. Since true bugs (Hemiptera) include aphids, leafhoppers, spittlebugs, thrips, whiteflies, and scale insects, I am all for more chalcid wasps! [Plus, I love figs!]
Figs and tiny wasps
While most chalcidoid wasps parasitize all those pests, a handful of them are phytophagous, which means the larvae hide and feed in stems, galls, seeds, and flowers. Fig flowers, in particular, are hidden clusters found inside a hollow structure called a syconium. Fig pollination is usually completed by tiny specialized wasps, such as chalcid wasps.
But, not all chalcids are good.
Chalcids as pests
Other phytophagous chalcids are not so helpful. These tiny wasps are pests because they lay their eggs in seeds. When those eggs hatch, larvae eat the seeds of pistachios and alfalfa, among others, creating burrows and allowing fungal and bacterial diseases a point of entry.
In many cases, sticky barriers can be used to reduce the damage caused by these pests. Most chalcids, however, are beneficial.
You can attract chalcid wasps to your garden by installing insectary plants, such as yarrow.
Wasps may have a bad reputation, but there are beneficial wasps, and ichneumon wasps [pronounced ick-NOO-mon] are one of those Good Guys. Well, mostly.
Ichneumon wasps are parasitic wasps and they have been around for over 15 million years.
There are somewhere between 60,000 and 100,000 different ichneumon wasp species in the world, with 5,000 species in North America. Clearly, with those numbers, there is significant variety in appearance.
Ichneumon wasp description
Like other wasps, the ichneumons have a narrow body and an even narrower waist. Some females have an especially long ovipositor, which is often mistaken for a stinger. Ranging in length from 1/10” to over 5” long, they can be black, brown, yellow, or some pattern combination of those colors. These wasps have 16 or more segments in their longer than average antennae. Ichneumons are solitary wasps.
Common ichneumon prey
Adult ichneumon wasps eat little or nothing. Their larvae, on the other hand, are voracious feeders of beetle, butterfly and moth, wasp, ant, fly, and sawfly larvae and pupae or chrysalises. This is what makes ichneumon wasps so helpful in the garden. They also parasitize beet armyworms, some spiders, and wood-boring grubs.
Some ichneumon wasps do this by using their long antennae to detect prey, then inserting the ovipositor into the wood, plant, or soil, to strike their prey, piercing its skin and inserting an egg. Other ichneumon wasps crawl down the stems of aquatic plants to inject eggs into water-dwelling insects. Yet another ichneumon is the parasite of a parasite, making it a hyperparasitoid. This ichneumon lays its eggs in moth-eating ant larvae. She emits chemicals that confuse the ants as she does her deed.
Ichneumon wasp lifecycle
Most parasitic wasps lay their eggs on, in, or near their prey, but ichneumon wasps kill their prey outright and then lay eggs. When the eggs hatch, larvae feed on the host’s body. After hatching and eating their host, ichneumon larvae spin cocoons and pupate in or near the exoskeletons of their first meal. When they emerge from their cocoon, they are adult wasps who go in search of a mate.
These garden helpers do not sting and they are worth their weight in gold, so check before swatting at something just because it might be a wasp. [Swatting at wasps is usually a bad idea, anyway…}
One of the best ways to attract and provide for beneficial ichneumon wasps in California is to plant coyote brush (Baccharis pilularis) and to maintain hedgerows.
Sweet, juicy persimmons are easier to grow than you might expect.
There are many good reasons for growing your own persimmon tree, the first of which is they are not particularly fussy about soil and they are nearly pest-free. You don’t need to worry about chilling hours as much as with other fruit trees, and they bloom late enough in the season to avoid frost damage.
Persimmon is a tropical tree that grows best in Hardiness Zones 7 to 10, and they are large. Mature persimmon trees can grow from 15 to 60 feet tall and 20 feet across, with a lovely rounded canopy. Leaves are both glossy and leathery on top, with a brown, fuzzy undersurface. These leaves will fall off in autumn, being deciduous, but that makes it easier to prune and manage the tree during dormancy.
Your first decision, when growing persimmon, is to decide which type you want.
Types of persimmon
Persimmons are actually the fruit of several trees in the Diospyros (‘Zeus’s wheat’) genus. This group of trees is divided between valuable, dense ebony lumber (Diospyros ebenum, et al) and fruit-producing varieties. Within the fruit-producing varieties, there are some you can eat right away, and some you’d be better off waiting a while.
The North American native persimmon (Diospyros virginiana) tends to be smaller and seedier than its more popular Asian cousin (D. kaki). The Oriental, or Japanese persimmon is further divided into two groups: astringent and non-astringent. That astringency [read ‘pucker factor’] is caused by tannins. Those tannins can make your mouth feel as though you just washed your mouth out with witch hazel, which I do not recommend. Generally speaking, the astringent varieties need to be fully ripe and soft before becoming sweet and delicious.
With over 2,000 cultivars of fruit-producing persimmon trees, you have several to choose from, including:
Native and Oriental persimmon trees will not cross-pollinate.
Persimmon fruits and flowers
Native persimmon trees are dioecious, meaning they have male or female flowers, but not both. If you have one of these, you will need two trees. Oriental persimmon trees have both male and female flowers. In either case, those flowers are relatively small, creamy white, with a large green calyx. The calyx is the cup-like structure seen at the base of a flower’s petals and is the hard, dried leaves on top of a harvested persimmon. Botanically, a persimmon fruit is a berry because it is formed from a single fertilized plant ovary.
Fruits mature in autumn, staying on the tree into winter. Don’t be fooled, however. Squirrels and rats have an uncanny ability to gnaw the insides out of your persimmons from the side facing away from your windows. I have a friend who discovered, to her dismay, that every single piece of fruit, and there were many pieces of fruit, had all been hollowed out while she wasn’t looking.
If you only have room for one persimmon tree, just make sure it is a self-pollinating variety. Both ‘Hachiya’ and ‘Fuyu’ will produce fruit without a second tree.
How to grow a persimmon tree
If you want to grow a persimmon tree from seed, you will need to put it in the refrigerator for a couple of months. This is called stratification and it mimics the effects of winter weather. Unlike other fruit trees, which are pretty much companionable to a wide variety of root stock grafts, persimmon trees are not as amenable. You are probably best off buying bare root stock from a reputable seller. Just be gentle with your young tree. The immature taproot breaks easily.
Persimmon trees perform best in soil with a pH of 6.0 to 6.5, which may be more acidic than is present in your soil. Keep in mind that altering pH is an uphill battle that requires constant attention and effort. If you are determined, you can acidify your soil to make things more hospitable for your persimmon tree. Your persimmon tree will benefit from good air flow, but the wood tends to be brittle, so provide protection from strong winds.
When planting a young persimmon tree, it is critical that the tree is planted at the proper depth. Then, cut the aboveground portion down to 3 feet in height and mud it in well. You will also want to provide sunburn and herbivore feeding protection. Deer, rats, squirrels, birds, and gophers will gnaw roots, stems, bark, or fruit, depending on the species. Even coyotes enjoy the occasional persimmon.
Select a location with plenty of sunlight, though partial shade will work, too. California Rare Fruit Growers, Inc. suggests keeping persimmon trees away from eucalyptus trees. I’m sure there is a good reason, I just don’t know what it is.
Regular irrigation will improve fruit size and quality, though the trees are somewhat drought tolerant. Mature trees will need 36 to 48 inches of water each year.
Persimmon trees do not need a lot in the way of feeding. In fact, if you give them too much nitrogen, they will drop their fruit! Over-feeding, over-watering, and too much boron in the soil can cause blossom drop and young fruit drop. Top dressing with aged compost and some mulch is probably a better way to go, unless a lab-based soil test tells you some important plant nutrient is missing.
Persimmon fruit forms along the sides and at the tips of long, current year stems. If those stems are too long, the branches are likely to break. During the dormant season, train your persimmon tree into a modified central leader or open vase system, removing any dead, diseased, or rubbing branches. Each year, you will want to perform light to medium pruning for size, structure, and air flow. Persimmon can also be pruned into a lovely espalier. Heavy fruit loads can cause branch loss, so fruit thinning is a good idea.
Persimmon pests and diseases
While relatively pest-free, persimmons may occasionally be attacked by root nematodes, mealybugs and scale insects. If you see ant trails, look more closely for signs of scale infestation. You can use sticky barriers to eliminate the protection provide by ants. Other minor pests include whiteflies, thrips, and mites.
The diseases most likely to impact a persimmon tree include armillaria root rot, grey mold, leaf blight, leaf spot, and Phytophthora root and crown rot. Fusarium dieback may also occur.
More commonly, nutrient deficiencies can cause a number of symptoms. Low iron cause cause leaf bleaching, while insufficient calcium leads to leaf curling, and magnesium deficiencies cause brown spots on leaves. Sunburn damage is common, so whitewash exposed areas and keep trees well irrigated during the peak of summer.
We should all have such problems…
You buy a seedling.
You dig a hole. You place your fingers around the stem and gently flip the pot upside down, dislodging plant and soil.
You carefully tip the leaves skyward and lower the cube of roots and soil into the hole, pulling surrounding soil into the empty space. Then you tamp down the soil with your hands, right?
We’ve been doing it forever but it’s the wrong thing to do and there are several reasons why.
It all starts with the conditions under which seedlings are grown.
The state of a seedling
Commercially available seedlings start out life in as perfect an environment as possible. Protected by greenhouse walls or hoop shelters, temperatures, soil, moisture levels, nutrient availability, everything is working in its favor. Add sunlight and water and those seeds germinate and start growing like crazy. Then they get loaded into flats, which get loaded onto trucks. Those trucks are dark and bouncy. Roots and leaves get rattled around a bit, before being moved a few more times to end up in new lighting, new temperatures, and environments where people pick them up and put them down, repeatedly. Finally, they get in a car, go home, and [hopefully] spend some time in quarantine before being designated some garden real estate.
Even seedlings started at home end up in a pot that they are about to outgrow, if they haven't become root bound already.
As delicate root hairs reach the walls of their containerized world, they twist and turn, looking for more room. Eventually, all those twists and turns can get crowded and a little abrasive. Root hairs break off very easily.
At 1/10 the diameter of a human hair, root hairs start forming right after a seed germinates. These tiny growths profoundly increase the surface area of the root system, making the roots better at absorbing water and nutrients, anchoring the plant, and facilitating microbe interactions. When these delicate hairs break off, they can’t do their job. It is the damage done to root hairs during transplanting that causes most of the wilting associated with transplant shock.
Water and gravity
Instead of tamping down the soil and breaking off millions of valuable root hairs, let water and gravity do the job the way nature intended: disrupted soil gets rained on, rain drops collect and make soil heavier, drawing particles down into some air pockets while leaving important macropores and micropores, that allow air, water, and roots to move through the soil, intact. Your watering can or gentle garden hose spray do the same thing. No tamping down required.
As you add seedlings to your garden, resist the urge to crush those delicate root hairs and mud them in, instead. Then, tuck them in with a nice blanket of mulch, for good measure.
Cantaloupes are a unique type of muskmelon. And American cantaloupes aren’t actually cantaloupes at all.
Did you know that melons are actually berries?
It’s true! Because the fruit, or pericarp, of a cantaloupe is produced by a single ovary, cantaloupes are considered berries. Specifically melons are modified berries called pepos. Pepos are formed from an inferior (meaning internal, not less than) ovary and they feature many seeds. Pumpkins and cucumbers are also pepos.
Also known as rockmelons, cantaloupes are members of the squash family. Like other cucurbits (Cucurbitaceae), cantaloupes feature a hard outer rind that protects the lush fruit inside.
Types of cantaloupe
Here, in the U.S., our cantaloupes have a strongly textured, or ribbed, rind and bright orange flesh. This North American variety (Cucumis melo var. reticulatus) is not technically a true cantaloupe.
How cantaloupes grow
Cantaloupes are vining annuals that love heat. Temperatures between 85°F and 95°F are ideal, and these plants can tolerate temperatures as high as 104°F. Cantaloupe’s bisexual flowers are mostly pollinated by bees, so a healthy bee population is important for a good melon crop. Whereas a single bee visit is enough to pollinate other crops, cantaloupes are fickle and may need 10 to 15 bee visits before pollination is completed.
Cantaloupes can be grown successfully in all types of soil and they even seem to thrive in our heavy clay, as long as there is good drainage. Cantaloupes are sensitive to root rot diseases, so proper soil aeration goes a long way toward keeping cantaloupe plants healthy.
To grow your own cantaloupes, wait until temperatures are well above 60°F and plant single seeds 3” to 6” deep in loose mounds. Mounds should be 3 feet apart and in full sun. Keep the mound moist, but not soggy, until germination occurs.
Cantaloupes are moderate feeders, which means a top dressing of aged compost after germination is probably all that is needed. [Of course, you should still conduct a soil test to make sure your plants have access to all the nutrients they need.]
Cantaloupe pests and diseases
Aphids, green peach aphids, in particular, cucumber beetles, cutworms, leafhoppers, leaf miners, root knot nematodes, seed-corn maggots, silverleaf whiteflies, spider mites, squash bugs, and wireworms may all pester your melons, but many of these pests can be thwarted by row covers and regular monitoring. The real threat to your melon crop is disease.
Cantaloupes are prone to several fungal diseases, including belly rot, downy mildews, Fusarium wilt, Monosporascus root rot, powdery mildew, sudden wilt, and Verticillium wilt. Aphid-borne viral diseases, such as cucumber mosaic virus, cucurbit yellows stunt disorder, watermelon mosaic virus, and zucchini yellows mosaic virus may also occur, as can bacterial angular leafspot.
Proper plant spacing and the use of a trellis can interrupt many of these diseases cycles by improving air flow. Fruits grown up a trellis will need to be supported with hammocks. Melons growing on the ground should be protected with a layer of straw or sawdust, a board, or some other material that gets them up off the soil.
Choosing resistant varieties, removing weeds, maintaining good air flow, and avoiding overhead watering will all help keep your melon vines healthy.
That being said, weeds can be a serious problem in cantaloupe beds as hideouts for pests and diseases. Stay on top of those water and nutrient thieves from the start to ensure a healthy crop of melons later in the summer. And watch your watering. Heavy rain (or over-watering) can cause fruit split.
Cantaloupes are ready for harvest when a thin crack can be seen encircling the stem end and the fruit comes away from the vine easily. This is called the “full slip” stage. Cantaloupes should be eaten as soon as possible after being harvested, as they tend to lose moisture more quickly than many other members of this family. If you end up with a bumper crop of melons, your best method of preservation is to try your hand at canning some preserves. Cantaloupe pairs nicely with peaches and nectarines. And be sure to save seeds for next year's crop!
The majority of the world’s cantaloupe crop is grown in China and shipped around the world. Believe me when I tell you that harvesting a fresh melon from your yard is a very satisfying and delicious experience.
And halved cantaloupes make lovely ice cream bowls...
Cumin’s pungent aroma has made it a popular spice since ancient times.
Kept on Egyptian tables the way we use salt and pepper, cumin is said to provide many different health benefits, though there is zero scientific proof for any of those claims, There are still plenty of other good reasons for growing your own cumin.
Cumin’s umbrella-shaped flowers make it easy to identify as a member of the parsley family. Other common garden Umbellifers, or Apiaceae, include carrots, celery, dill, parsnips, and fennel. Like other umbellifers, cumin flowers attract many beneficial insects, such as hoverflies and pollinators.
Native to the Middle East, cumin (Cuminum cyminum) grows best in hot, dry regions and is very drought tolerant. It takes 3 to 4 months of hot weather to reach maturity. If temperatures drop, leaves will turn purple. If it gets really cold, cumin is very susceptible to frost damage.
The cumin plant
Cumin seeds look a lot like caraway seeds, being oblong with ridges. Those ridges are oil glands. Cumin plants grow 12 to 20 inches tall, with attractive, feathery leaves. Cumin seeds are contained in dried fruits called achenes.
How to grow cumin
If you have the heat, you can grow cumin. Seeds should be planted 1/4 deep and spaced 8” apart. These plants are very delicate when they first germinate and do not perform well in heavy clay soil. They prefer loose, sandy soil with good drainage, which makes them an excellent choice for raised beds. The ideal pH is 6.8 to 8.3.
Cumin pests and diseases
Aphids, mites, thrips, tobacco caterpillars, cutworms, cigarette beetles, drug store beetles, and root knot nematodes may cause problems for cumin. Diseases that may strike your cumin plants include Fusarium wilt, blight, powdery mildew, and damping off disease.
Cumin seeds are frequently included in birdseed mixes, so this plant has spread globally. Once established, this annual plant readily self-seeds an area.
In 2015, dreaded chili thrips arrived in California from Texas and Florida. Originally from Southeast Asia or India, this pest first hit North America in 1991 and is expected to be a permanent part of our gardening experience from here on out.
Let’s see what we’re up against.
Before we do that, however, let’s get one thing clear. Whether you are talking about many thrips, or just one (and there is never just one), they are both referred to as “thrips”, with the “s” on the end. I know, it’s strange, but there it is. It comes from an 18th century word meaning “woodworm”, which is even more strange since these pests are disease-carrying sap-suckers.
So, what does a thrips look like?
Chili thrips description
Like other thrips, chili thrips (Scirtothrips dorsalis Hood) are really tiny - often less than 1/20” long. That works out to 8 or 9 thrips, standing nose-to-tail, across the head of a dime. Their pale bodies are thin and they have dark wings, but you may never get that close. What you may see is light-colored flecks of movement as you walk past a plant. That’s your first clue there is a problem.
Plants vulnerable to chili thrips
Your habaneros and Scotch bonnets are not the only plants susceptible to these pests. In fact, over 100 species [no, make that 200 species], from 40 different plant families [rather, 70 families], have been identified. Host plants include fruit trees, such as apples, bananas, cashews, citrus, figs, lychee, mango, pears, and even the beloved cocoa bean. Other garden favorites include asparagus, basil, beans, blueberries, buckwheat, corn, eggplant, grapes, peanuts, sweet peppers, soybeans, strawberries, and tomatoes, as well as many popular ornamentals, including chrysanthemums, coleus, camellia, Gerber daisies, poinsettias, pyracantha, roses, snapdragons, and zinnia.
Damage caused by chili thrips
Symptoms of chili thrips infestation are first seen as damage to the upper surfaces of leaves, creating yellowish-green or brown angular spots on the upper surface and a grey sheen on the under surface. Leaves may become thickened or start curling. As nutrients and water are pulled from the plant, stunting, bronzing, distorted or elongated leaves, and flower bud scarring are also seen. Severe infestation can lead to the complete defoliation of a plant and these pests can carry tomato spotted wilt virus, peanut necrosis virus, peanut chlorotic fan virus, and tobacco streak virus.
Compounding the problem, chili thrips damage looks a lot like chemical overspray, aphid feeding, and micronutrient deficiencies.
Chili thrips lifecycle
Female chili thrips insert eggs into leaves, petioles, fruits, leaf axils, in curled leaves, and in leaf litter. In other words, they can be anywhere. Those eggs hatch in about one week and go through two larval stages in the second week. A single adult female can lay 60 to 200 eggs in her lifetime. That works out to a lot of sap sucking, disease-carrying insects.
Controlling chili thrips
Fast moving, highly prolific, and devastating to many of our garden plants, chili thrips have already developed resistance to insecticides containing asbifenthrin, cyfluthrin, and permethrin, so don’t bother. As of 2016, chili thrips had not yet developed resistance to insecticides containing acephate, imidacloprid, and orspinosad, but that window of opportunity may already have passed, and who wants those chemicals on their food anyway? Spinosad is actually more effective and less damaging to the environment. Sticky barriers may be used to monitor for chili thrips, but they won’t control the problem.
Your best defense against chili thrips is to encourage beneficial insects, such as green lacewings and minute pirate bugs. Certain predatory mites and thrips and parasitic wasps will also help in the battle against chili thrips. These garden helpers are all attracted to gardens with a wide variety of plants and flowers, a clean water supply, and the absence of broad spectrum pesticides. Sadly, releasing purchased predators into the garden rarely works out. If conditions are good, they will come to you. If conditions are not good, it doesn’t matter how many times you buy and release beneficial insects. They will simply leave or die.
Dusty conditions should also be avoided. Give susceptible plants an occasional quick shower with the garden hose in the morning to make life more difficult for thrips of all sorts. Also, stressed plants are more susceptible to infestation than healthy plants. This is yet another reason for selecting resistant cultivars that are suited to your microclimate, putting them into quarantine until proven healthy, feeding and watering them when they need it, and then giving them a helping hand with row covers as they become hardened off to your garden. Since shearing cuts off the ends of all twigs, it should be avoided if thrips are suspected. It is simply too stressful for the plant. Reflective mulch may disrupt thrips flight, if you want to try that.
Infested foliage should be removed, bagged, and taken to your local County Extension Office for identification. If you don’t have time for that trip, please throw the bag in the trash. Do not compost plant material infested with even one chili thrips.
Western grape rootworms are leaf beetles that eat the leaves of grapes, roses, and fireweed in spring and summer. If that weren’t bad enough, their offspring are found underground, chewing up the root system. The combined effect can be devastating.
Western grape rootworm description
These beetles are very small, averaging only 1/7” in length. This works out to 4 or 5 beetles standing end-to-end across a dime.
Unlike their more tan-colored cousins, western grape rootworms are usually black or reddish-brown with dull gray, yellow, or white hairs, and orangish-red antennae. Larvae are 1/4-inch long, C-shaped white grubs. These grubs have 3 pairs of prolegs, a reddish brown head, and black or brown mouthparts. Eggs are laid in clusters on old wood under loose bark.
Male western grape rootworm beetles rub their legs together to attract females, the same way crickets and grasshoppers do each summer.
Damage caused by western grape rootworms
These beetles cut slit-like holes in leaves, shredding them to tatters. The leaves then dry up and die, reducing photosynthesis and food for the plant. Adult beetles may also be found feeding on berries, petioles, and the bark of new shoots. Underground, western grape rootworm larvae feed extensively on the root system and can cause considerable damage.
Controlling western grape rootworms
Since larvae spend most of their year 2-feet underground, control is generally only possible during spring, when larvae and adult beetles move to the surface. Monitor plants for signs of beetle feeding and handpick whenever possible. You can also use sticky barriers to capture beetles moving up and down the trunk.
If you see a tiny beetle playing ‘possum, don’t be fooled. The western grape rootworm beetle uses that trick to avoid being eaten, often falling off a leaf, stiff-legged.
With a name like Asian jumping worms, you might expect colorful, flamboyant gymnastics moving gleefully through the soil, helping your plants grow.
Okay, that was a stretch. And you’d be mostly wrong.
I say mostly because, while not colorful, these worms really can move. Also known as snake worms, crazy worms, and Alabama jumpers, Asian jumping worms writhe violently when disturbed. They can even drop their tail when threatened.
Sadly, instead of helping plants grow, these voracious feeders strip an area of nutrients, destroying the top soil layer, and leaving desolation in their wake. This interrupts thousands of years of evolution and nutrient cycling, threatens biodiversity, and increases erosion.
The invasives mixed bag
Before we get into the Asian jumping worm story, let me remind you that our beloved European nightcrawlers and honey bees are also non-native species. Sometimes invasives can be a good thing. This is not one of those times.
As with many other situations involving invasive anything, the problem lies in imbalances. North American forests and farmlands have evolved, over thousands of years, to use surface plant litter as slow-release food and secure habitat for countless microorganisms, insects, reptiles, amphibians, and other life forms. Asian jumping worms eliminate that layer and they do it very quickly.
What are jumping worms?
Our more sedate earthworms tend to be reddish brown with a raised white or grey partial band part way down the body. That band is called the clitellum. Asian jumping worms, which can range from 3 to 7” long, are grey to dark brown, with a smooth the clitellum that goes all the way around and is closer to the head end.
Also, while shiny, jumping worms do not produce the slime seen on many earthworms. Regardless of how you feel about that slime, it is very useful in creating soil aggregates that allow for the healthy movement of air, water, microorganisms, and roots through the soil. Jumping worms also tend to be more rigid than our squishy earthworms.
There are three species of Asian jumping worm: Amynthas agrestis, A. tokioensis and Metaphire hilgendorfi, with A. agrestis being the most commonly seen. Native to Southeast Asia, jumping worms are believed to have been brought to North America in potted plants, bagged soil, or nursery stock, though we don’t know exactly when or how.
Asian jumping worms have moved quickly westward, in worm terms, over the past 10 years and are now found in Oregon. As you can imagine, these continued movements are not just worms traveling on their own. Asian jumping worms end up in plants, mulch, and soil, on shoes and equipment, in agricultural produce, and in batches of fishing bait. They get transported by us, one gets loose, the problem spreads. It’s easy to do because these jumping worms spend their winters as tiny, pinhead size cocoons, filled with eggs, they reach adulthood twice as fast as our familiar earthworms and red wigglers, reproduce more rapidly, and are more aggressive. They can also thrive in higher densities and eat a wider variety of foods.
The real problem with Asian jumping worms is where and how fast they feed.
Damage caused by Asian jumping worms
Asian jumping worms are too efficient. That may sound like a good thing, but too much of a good thing can be a bad thing. Let me explain.
As earthworms feed on fungi and bacteria that grow on decomposing organic material, they burrow into the soil, excreting castings that are filled with broken down plant and animal material, churning the soil and improving soil structure, soil health, water retention, drainage, and nutrient cycling. Everybody’s happy. Plants and organisms grow. Life goes on.
Asian jumping worms are eating machines, quickly devouring all of the surface material in an area and leaving behind a trail of low-nutrient crumbles prone to serious erosion. Research has shown that jumping worm castes are different from those of other worms. Instead of the soft, brown, crumbly bits of plant food and soil amendment we associate with earthworm castings, Asian jumping worm castings look more like a pile of coffee grounds.
Asian jumping worms process nutrients so rapidly that their feeding releases nutrients faster than plants can absorb them, causing the nutrients to be washed, blown, or leached away. These castings contain important plant nutrients, such as potassium and calcium, and they tend to contain higher levels of heavy metals, such as iron and aluminum. When those crumbles are eroded away, those nutrients are lost. As a result, Asian jumping worm feeding quickly converts healthy, loamy soil in to granular, more sandy soil that tends to be hydrophobic, which means water runs off instead of sticking around long enough for plants to absorb. These invasive worms also push nutrients so deeply into the soil subsurface that many shallow-rooted plants cannot reach those important nutrients, leaving them to starve.
What can you do about jumping worms?
In a word, be diligent. Asian jumping worms generally cannot survive freezing winters, but anything less than that and they can become a serious problem in your yard. You can help prevent the spread of these invasive worms with these handy tips:
Bottom line, earthworms create topsoil while Asian jumping worms destroy it. Of course, that’s an oversimplification, but I want you to understand how important it is that these pests are kept in check.
If you suspect the presences of Asian jumping worms in your garden, conduct a mustard test using these steps:
Hollyhocks are probably not your first thought when it comes to edible gardening, but these tall, bold beauties of our grandparents’ time may surprise you.
First, did you know that all parts of a hollyhock are edible? My chickens may not share that world view, but we frequently differ on menu items.
In addition to being edible, hollyhocks are surprisingly useful plants. Hollyhock stems make excellent starter firewood, and the roots have been used for centuries as medicine. While I do not make any medical claims about plants, research has shown that infusions of hollyhock roots may reduce stress. I’ll leave that to you.
Let’s see what else we can find out about these durable garden flowers.
Hollyhocks are members of the mallow family. Native to Europe and Asia, there are 60 or so species of hollyhock, or Alcea, with Alcea rosea being the most commonly grown. The Alcea genus includes all the hollyhocks, except for one species that is native to the western hemisphere, the streambank wild hollyhock (Iliamna rivularis).
While the streambank wild hollyhock is in a different genus, the blooms are still lovely. For this post, we will be focusing solely on Alcea hollyhocks.
Hollyhock flowers are impressive. Growing along the stalk like flagrant Brussels sprouts, large hollyhock blooms can be pink, red, apricot, raspberry, bluish pink, white, purple, or yellow. Their sturdy, unbranched stems can be equally impressive, rising 3 to 10 feet in the air, depending on the variety. There is even a nearly black cultivar, called ‘Creme de Cassis’.
Broad leaves may be toothed or lobed and grow on long stems called petioles. Both leaves and stems are generally covered with star-shaped trichomes, or hairs. While those hairs may irritate your skin, if you are sensitive, it is the hollyhock flower that grabs our attention.
Caring for hollyhocks
Hollyhocks are not particularly picky. They grow best in Hardiness Zones 3-8, can be grown in full sun or partial shade, and prefer good drainage. The only thing hollyhocks do not seem to like is dry soil. Here in California (Zone 9b), dry soil is the rule in summer, but a thick layer of arborist chips mulched over the area and planting them in a relatively protected corner of the yard seems to be help enough and they return every spring to fill my summer with gorgeous flowers. Being near a fence or trellis also protects these tall stems from wind damage.
To keep your hollyhocks healthy, cut stems back to 6” or so above soil level after flowering is completed. Continue to top dress and irrigate the area and new stems will appear throughout the growing season. In winter, cut plants back again and protect with a 6” layer of straw or mulch. Come spring, gradually remove this protective layer to help plants become acclimated. Once spring growth is in full swing, remove the straw and start thinning.
By removing the cut stems from the area and composting them, you will interrupt the disease triangles and thwart pests of hollyhocks.
Hollyhock pests and diseases
On the downside, like other members of the mallow family, hollyhocks are prone to mildew and rust and will attract weevils, mallow flea beetles, and orange tortrix moths. The caterpillars of a few other moths and butterflies, including painted ladies, will also chew on hollyhock leaves, as will slugs and snails, spider mites, and Japanese beetles. Aphids, capsid bugs, and cutworms may also cause problems.
Because they are prone to rust and mildew, hollyhocks should always be watered at ground level. Wet leaves nearly always attract disease. Diseased leaves should be removed and thrown in the trash whenever they are seen.
Hollyhocks and children
Hollyhock seeds are large and easy to work with, making them a good choice for a children’s activity. Hollyhocks do not like being transplanted, so it is better to sow seeds where you want them. A hollyhock’s long taproot doesn’t like being disturbed, once it begins its downward growth.
Traditionally, hollyhocks have been used to create secret garden spaces for children and solitary readers. Simply draw a line where you want you secret hideaway’s walls and plant seeds along that line. Seeds should be planted in groups of 3 or 4, placed 2 to 3 feet apart. Only cover lightly with soil, if at all, and keep the area moist but not soggy until germination occurs. Thin each group by snipping off all but the best one seedling at ground level. They may look tiny and lonely, at first, but these plants get large and need good air flow to stay healthy.
Before you know it, you will have a secret garden space of your very own, attended by the many bees, butterflies, hummingbirds and other pollinators that love hollyhocks as much as we do!
Worms, or wyrms as they were originally called, don’t technically exist.
Wyrms referred a huge collection of tubular, limb-less critters back in the 1700’s. Of course, we all know what I mean when I say worm, right? Sure, we’ve all seen earthworms and red wigglers. But what about the 3-foot bristle worms, or the 22-foot African giant earthworm, or, are you ready for it? What about the 190-foot oceanic bootlace worm?!!? Crazy, right?
Well, clearly, we don’t ave any 190-foot worms in our gardens. What we do have is long, squishy bodies that are easier to describe by what they don’t have. Worms do not have legs, true limbs, scales, lungs, a brain, a true digestive system, or a circulatory system. They breath through their skin, which needs to be moist at all times. Dehydrated worms become paralyzed.
You may be surprised to learn that many worms are not actually able to move themselves with muscles, the way we do. Instead, they move through the soil by the act of feeding. If you think about it, worms are one big food tube. Food is sucked into the mouth and passes through a pharynx, esophagus, crop, gizzard, and intestine, before being pushed out the other end. While worms do not have eyes, per se, some of them do have light sensing organs.
Types of garden worms
There are three different types of garden lifeforms that fall under the worm category:
Nematodes are round worms. Earthworms are segmented. And flatworms, such as land planarians are, well, flat. The flatworms and roundworms are known as helminths and tend to be parasites of one form or another.
Worms improve soil
Worms are an important part of decomposition, whether it is happening underground or in your compost piles. Worms improve soil structure and soil health, making life a lot easier for your plants. As worm populations increase, drainage and porosity, or permeability also improve.
As worms eat, poop, and die, they create mucous-coated soil clumps, or aggregates, that have spaces for water, roots, and air to move through. These spaces, called macropores and micropores, are important factors in soil health. For example, in sandy soil, the spaces are very large and leaching can be a problem, while clay particles are very tiny and they hold tightly to water and nutrients, and often have compaction problems. Worms help offset those problems by helping to break down and decompose organic materials, improving soil structure, adding nutrients, and being part of the nitrogen cycle. Worms are an important part of the soil food web and they help keep plant and tree roots healthy.
Food for worms
Did you know that earthworms like coffee? It ends up that sprinkling coffee grounds around your yard is a good way to reduce compaction and a couple of fungal diseases. For some reason, worms tend to pull coffee ground deeper into the soil. We don’t know why. We do know that worms will eat dead plant material, insects, insect eggs, fungi, bacteria, dead animals, and even cardboard and paper.
While we may all end up as food for worms, more often than not, it is the worms who become the entree. Worms are commonly eaten by birds, amphibians, reptiles, and many mammals. Skunks, moles, shrews, raccoons, and rats will all gobble a worm, given the opportunity, as will centipedes, beetles, and even other worms, such as land planarians.
Worms that are not worms
Caterpillars, such as the impressively large Achemon sphinx moth, carpenterworm, and tomato hornworm larvae are commonly referred to as worms, as are tiny pink codling moth larvae, apple maggots, armyworms, cutworms, inchworms, naval orangeworms, and destructive green cabbageworm larvae, as are the microscopic larvae of dryberry mites. The larval form of click beetles are also called wireworms. And some people call grubs worms, too, but I have no idea why Each of these not-worms is simply a developmental stage in a process of metamorphosis..
Help the worms in your yard
Worms do not have much of an arsenal when it comes to defense. The best way to help the worms in your yard is to create a healthy environment that meets their needs. If you build it, they will come. These tips will help you create a worm-friendly habitat in your yard:
If you happen to use tower gardening or other containerized methods, you can always rescue a few worms stranded after a rain and add them to the pot. They and your plants will be better of! And if worms really fascinate you, you can also raise your own. This is called vermiculture.
Your yard may look quiet on the surface, but there is a lot going on underground. Even when given time to rest, or go fallow, there are still billions of processes happening in the soil beneath your feet, and worms are an important part of those processes.
Finally, there is a new threat in the world of soil organisms. This one is the Asian jumping worm. There will be more on that soon.
Long, long ago, there were no flowers.
It wasn’t until the Cretaceous period, some 130 million years ago, that a handful of renegade cone-bearing gymnosperms started protecting their naked seeds with a new structure. This new, flimsy bit of color was so successful at boosting pollination rates that it spread far and wide, making flowering plants (angiosperms) one of the most successful types of plant life on Earth.
That structure is the petal.
Of course, that’s a pretty big claim for such a delicate flap of plant tissue. Too frequently discounted as an unimportant fashion accessory to more vital, functional parts of plant anatomy, there is far more to a flower petal than meets the eye!
Before we get to the really astounding stuff, let’s make sure we know what we are talking about when we talk about petals.
What are petals?
You may be surprised to learn that petals are modified leaves. In fact, sepals, stamens, and carpels are all genetic twists on the leaf. As a modified leaf, a petal has a broad, flat area called a blade. At the narrow end, where the petal attaches to the plant, is the claw, which is very similar to a petiole, or leaf stem. Where petals are attached to one another is called the limb. The petals that make up a flower are called its corolla.
Just under a collection of petals is another set of modified leaves, called sepals. Sepals are usually green. When discussing the combined petals and sepals of a flower, it is called the perianth. When sepals and petals are indistinguishable from one another, they are called tepals. [Aloes and tulips are tepals.] Sometimes, sepals look more like petals than leaves. When that occurs, they are said to be petaloid.
Petals of parentage
The number of petals present in a flower, the way the petals are arranged, whether or not they are fused to neighboring petals, or how much they are fused, as well as color are used by pollinators to find the pollen and nectar they seek. We can use the same information to identify unknown plants
First, flowers with 3 or 6 petals tend to be monocots, while flowers with 4 or 5 petals, or groups thereof, are most often eudicots, though not always. Petal arrangement, or floral symmetry, can also help with plant identification:
Petals, in particular, evolved to protect the reproductive part of a flower and to attract or repel specific pollinators. We know that flowers come in every color imaginable, but did you know that they also feature colors we cannot see, with glowing flight lines, traffic patterns, and welcome mats? It’s true! Flowers exist to attract the type of pollinator that will help them to procreate their species. Not all pollinators are created equally. It is a waste of resources for a plant (or any living thing) to attract the wrong sort.
The story of floral scent
Orchids produce floral scent in specialized sacs, but most flowers get their scent from chemicals produced by the petals. While many of us, along with most insect and bat pollinators, find floral aromas appealing, herbivores and disease-carrying insects often disagree with that evaluation. Combined with the colors, petal arrangement, and floral placement, floral scent works to increase a flower’s chance at becoming pollinated and/or fertilized.
Did you know that plants use floral scent to communicate with each other? It’s true! The volatile chemicals that give a flower its fragrance trigger a behavioral response in a surprising number of neighboring life forms and no two floral scents are identical, sort of like snowflakes.
Sensing a reproductively fertile neighbor, another flower may shift its chemical production to attract pollinators of its own. On the other hand, a fertilized flower will often release ethylene, a ripening agent, to discontinue the scent so that local pollinators will turn their attentions to neighboring flowers in need of pollinating. Also, injured flowers produce different scents than those being chewed on by herbivores. We can’t see it or smell it, but it’s going on all the time.
In the world of botany, a cane can refer to a stalk of bamboo or other grass, a reed, sugar cane, or new growth on a grape vine. Canes are also used to refer to blueberry, currant, rose, and kiwi stems, but we will leave them out for the sake of this discussion, which is more accurately geared toward blackberries and raspberries.
Canes are the long, arching stems of perennial bramble fruits. These canes are filled with spongy pith and normally covered with sharp prickles. Because of those sharp points, bramble canes have traditionally been used in pleaching. Pleaching is method by which living bramble are cut in half, bent over and woven together. As the canes repair themselves, they create a dense, prickly barrier that few thieves or predators would care to cross.
Brambles have perennial roots and crowns that grow new canes each year. New green canes are called primocanes. They turn brown and go dormant over the winter, to one degree or another. In spring, these now 2-year old canes are called floricanes. Flowers and fruit are only produced on floricanes, so you don’t prune them out. Once fruit set has occurred, canes should be allowed to die back before being removed.
Cane growth forms
Raspberry and blackberry canes can grow in one of two forms: erect or trailing. Erect brambles have stiff canes that arch. While not completely self-supporting, erect brambles tend to grow into huge thickets if not pruned. Trailing blackberry cultivars, also known as dewberries, will spread horizontally across the ground. If you live in a cold area, there are even late-season blackberry varieties that can produce late summer crops. The University of California provides an excellent list of blackberry cultivars.
Cane fruit production
Cane fruit production varies between everbearing and summer-bearing varieties. Summer-bearing canes bear one crop in summer on two-year old canes, while everbearing cultivars have two crops, one small crop in summer on new canes and one heavier crop in fall on two-year old canes. Everbearing cultivars are sometimes called fall-bearing. It is a good idea to check with your local Cooperative Extension Office to find the best cultivar for your location.
Brambles can easily be propagated by a method of layering called tip layering. Tip layering consists of digging a small hole, 3 or 4 inches deep, and putting the tip of a cane into the hole and covering it with soil. At first, the tip will grow downward. Then, it will complete a U-turn in the soil and emerge above ground. That bend will develop roots, allowing the new plant to be separated from the parent plant in spring and replanted elsewhere.
New canes should be trimmed to a 6” height. First-year canes can be pruned to a manageable size with renewal pruning, or trained onto a trellis. Stimulate lateral (fruit-bearing) growth by tipping, or cutting off the ends. When working in bramble canes, it is a good idea to wear long sleeves, long pants, and heavy gloves. Those prickles are sharp!
Pests and diseases of canes
Canes are susceptible to a number of different pests and diseases. Bacterial diseases, such as crown gall, viral diseases, such as tomato ringspot, and a slew of fungal diseases, including a number of blights, such as petal blight, spur blight, and cane blight, along with leaf spot, anthracnose, rust, and Verticillium wilt may also appear. If that weren’t bad enough, treehoppers, raspberry cane borers and another type of borer called the rose stem girdler, along with sawflies, lygus bugs, raspberry horntails, vine mealybugs, , leafrollers, and tortricid moths (leaf roll) may feed on or damage bramble canes. For all those threats, canes are durable plants, once established. You do need to monitor for environmental conditions, such as dieback, insufficient calcium combined with infrequent irrigation, iron deficiencies, and sunburn damage.
Whichever cane fruit you decide to grow, you will receive many, many years of delicious summer fruits with surprisingly little effort. Just watch out where you plant them, they can spread!
The Daily Garden is all about plant vocabulary. Today, we are looking at overall plant anatomy because it can be difficult to talk about something if you don’t know the words.
By taking a closer look at plant anatomy, we will be better able to understand each other, we can get more out of plant descriptions, and be better able to identify those mystery plants that always seem to pop up in the yard.
Plant anatomy, or phytotomy, starts with simple descriptions of the outside and inside of plants. Remember those black-line masters from grade school used to teach parts of a plant? Well, let’s start there.
Basic plant systems
Plants are have two basic systems: roots and shoots, with the root system below ground and the shoot system above ground. Roots provide anchorage and often store nutrients. Roots can develop as a taproot or fibrous root system. Roots have hairs that absorb water and nutrients. The shoot system consists of vegetative parts (leaves and stems) and reproductive parts (buds, fruits, seeds, and flowers or cones). Let’s take a closer look at each of those parts.
Leaves are the sugar factories of the plant world, absorbing sunlight and converting it into sugar through photosynthesis. The wide, flat part of a leaf is called the blade, or lamina. The shape of the leaf blade is very useful in plant identification, as is the way those leaves are arranged along a stem and the pattern of veins within a leaf. The edge of the leaf is called its margin. Leaves are coated with a waxy protective cuticle. There are tiny holes, usually found on the underside of a leaf, called stoma, that allow plants to exchange gases with the environment and to regulate water flow within the plant. The stem that connects a leaf to a stem is the petiole. Leaflike structures seen at the base of the petiole are called stipules,
Stems support leaves, flowers and buds. These structures are attached at nodes. The spaces between nodes are called internodes. Herbaceous stems have waxy cuticles for protection while woody plants have bark. Stems contain a vascular system that consists of the xylem, phloem and may include a cambium layer. This system carries food, water, and minerals throughout the plant. That vascular system is arranged in a circular pattern in dicots and eudicots, while it is more scattered in monocots. Twigs are woody stems from the previous year. Branches are more than one year old and may have lateral stems. Trunks are the main stem of woody plants, such as trees and shrubs. Canes are a type of stem filled with spongy pith. Canes generally only live for a year or two. Modified stems occur both above and below ground. Bulbs, corms, rhizomes, and tubers, such as potatoes, are below ground modified stems. Crowns, spurs, and stolons are aboveground modified stems. Thorns are also modified stems, but rose thorns are not really thorns. They are prickles, which are modified epidural, or skin cells. Stubby stems, called spurs, produce fruit buds.
Buds are shoots that may develop into leaves or flowers. Buds are identified by their location on a stem: lateral buds are found along the sides of a stem, while terminal buds are found at the end. Lateral buds usually grow where leaves meet the stem and are called axillary buds. Renegade adventitious buds may show up at injury sites, on roots, or even at the edge of a leaf. The place where buds fall off leave a mark called a bud scar. Tree leaf buds have scales, while leaf buds of annuals and herbaceous perennials have delicate naked buds. Potato eyes are clusters of buds.
Fruits are ripened plant ovaries. Fruits can be simple (formed with one ovary), as in the case of stone fruits, or compound (formed with several fused ovaries). Compound fruits can be multiple or aggregate. Apples and other pomes are multiple compound fruits. You can tell by the 5-pointed star shape in the center of the fruit. Raspberries, which are drupes, not berries, along with pineapples and figs are formed by many flowers fusing together and are called aggregate fruits. By the way, strawberries are not berries, either. They are ripened receptacles. Berries, such as pumpkins, cantaloupes, cucumbers, eggplants, and tomatoes, all have many seeds inside an outer shell of varying thicknesses and hardnesses. Dry fruits, such as peas and beans, grow in pods that either open down a seam (dehiscent), or stay closed (indehiscent), as in the case of peanuts and most cereal grains, such as wheat and barley.
Seeds have three parts: the embryonic plant, stored food, called endosperm, and a protective seed coat. As temperatures rise and moisture is absorbed through the sed coat, a primary root, called the radicle, will emerge, followed by the first stem, or hypocotyl. First leaves, or cotyledons often look very different from adult leaves.
Flowers exist solely to attract pollinators. Only angiosperms make flowers. Gymnosperms, such as conifers, ginkgo trees, and cycads make cones, or strobili. The colors, patterns, showy displays, and sweet aromas we associate with flowers are all in place to attract insects, bats, and birds. Flowers are supported by a stem called a peduncle. Small green leaf-like structure, called sepals, are often seen at the base of a flower. A collection of sepals is called a calyx. Individual petals may produce nectar or scent. All of the petals together are called the corolla. The combined corolla and calyx are called the perianth. The tip of a flower stalk, called the receptacle, contains the plant’s reproductive organs. Flowers can be male, female, or both, though not always at the same time. The female part, or pistil, consists of a pollen-receiving stigma, supportive style, and the ovary. [When you eat saffron, you are eating the style and stigma of an autumn crocus flower.] The male part, or stamen, consists of a pollen-producing anther and a supporting filament. Flowers are very useful in plant identification.
Genetic research and electron microscopes have brought plant anatomy to exciting new levels. Assumptions about kinship have been wrecked asunder and colorized scanning electron microscope (SEM) images can be breathtaking. Different types of plant cells gather together to create tissues. Those tissues come together to create the functional parts of a plant.
Ultimately, all those functional parts grow into delicious, nutritious foods that we can cultivate in our yards for decades. For me, feet up in the yard with a nice glass of wine beats standing in line at a grocery store any day!
What do wedges of citrus, hard walnut shells, the white bits inside a pomegranate, and the paper coating around avocado pits have in common?
They are all endocarps.
How can this be? How can structures so very different be the same part? Let’s find out by starting with some basic fruit facts.
The fruits and seeds we eat are plant ovaries. When a flower is pollinated and fertilized, three new structures form: seeds, pericarp, and placentae. Embryonic seeds attach to the placenta, and pericarp begins to grow, to feed and protect the embryonic seed, and to attract seed-spreading herbivores. There are three different types of pericarp tissue: exocarp (outer skin), mesocarp (flesh), and endocarp (inner layer). So, endocarp is the interior fruit that surrounds seeds. But what about all those differences?
Types of endocarp
Endocarp is generally not fruit in the way you would expect, unless you are talking about peppers or citrus. The fleshy parts of sweet peppers and chili peppers is the endocarp, as are those membranous wedges of fruity goodness found inside lemons, limes, and oranges. If you look inside an apple, the endocarp is the hard clear plate-shaped bits close to the seeds.
If you take a close look at a stone fruit, such as a nectarine or cherry, the endocarp is very hard and inedible. To us, it looks more like the shell of a nut. And guess what? The hard outer shell of walnuts, pecans, and almonds, that shell is the endocarp, even though, to us, it looks as though it is on the outside.
Confused? Read on!
Nuts about endocarp
When a nut develops on a tree, the exterior rarely looks like what you see in the grocery store. Many nut species have smooth or furry green exteriors (exocarp). That exocarp coats a hard, familiar shell. That shell is the endocarp of a nut.
Stamens are the male aspect of a flower.
Flowering plants, or angiosperms, have flowers that can be male, female, or both, though not usually at the same time.
The word stamen comes to us from the Latin word for ‘thread’. This is because the stamen is a threadlike stalk, called a filament, which has a pollen-producing anther on top. The stamen usually surrounds the female part, or pistil, though not always
Different plant families have different arrangements of pistils and stamens. For example:
When eating edible flowers, it is a good idea to remove the stamen and pistils and just eat the petals and other parts. The only exceptions are violas and Johnny-jump-ups. In these cases, the other parts add good flavor. Saffron threads are the dried [female] styles and stigmas of a specific crocus flower species, not the stamen.
Melons, zucchini and other squashes can easily be hand-pollinated by breaking off a pollen-carrying stamen and touching each of the flowers flowers with it.
Now you know.
You can grow a surprising amount of food in your own yard. Ask me how!