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Features (Gardening)

But not so great for forests

Robins and sparrows sing the praises of our unending rain. Their beaks and bellies are filled with wriggling worms.
    Earthworms surface as wet conditions make easy work of relocating. No, worms don’t come up to escape drowning. They are capable of surviving several days submerged.
    The vibration of raindrops sounds like the predatory rumble of moles looking for a snack, causing the worms to head for the surface, where fishermen and hungry birds find them. Some birds have shifted to eating an earthworm-only diet.
    Gardeners also appreciate the nutrient-rich deposits our red wrigglers leave in our compost and soil. But their presence is causing a bit of havoc in our forests.
    “Every one of those earthworms you see on the sidewalks and driveways after a rain is an invasive,” Melissa McCormick says.
    McCormick is a research scientist with the Smithsonian Environmental Research Center in Edgewater, where she studies the interaction of plants with fungi. Including how invasive earthworms are changing the forest environment.
    “We still have a few native earthworms, but the vast majority are non-natives from Europe and Asia,” she says. It is possible that some of these visitors arrived as early as the first European settlers on this continent.
    As with human invasions, these wormy tourists have pushed out native species and caused trouble in the new land.
    “Forests are adapted to work with native earthworms and fungi to support late successional trees,” McCormick explains. Alien worms eat through leaf litter more quickly, baring soil to invasive plants. By affecting the nutrient cycle in the forest, invasive worms give bacteria and more aggressive fungi a favorable environment.
    The Smithsonian research team looked at populations of earthworms at test sites, digging trenches in blocks of soil and using electroshock to coax the worms out. They then planted tree seedlings to see what fungi grew and how the soil affected their growth. A healthy forest has many diverse layers and ages of trees.
    “Most native plants and trees are dependent on their association with fungi to get their nutrients,” McCormick says. “These large populations of invasive earthworms basically bias the soil against the fungi the trees rely on, especially late successional.”
    The experiment proved that oak, hickory and beech trees did not grow as well with lots of invasive earthworms around. Tulip poplar and red maple — both early successional species — grew just as well if not better.

Test your soil to put them to work

Horticulture is a science, not a guessing game.
    I can remember my pipe-smoking, tobacco-chewing grandfather putting garden soil in his mouth to taste if it was sweet or sour. I was impressed at the time, but looking back on his method of testing soil, I know it would have been impossible for him to make any determinations of the pH or of nutrients by taste.
    Just as doctors rely on blood tests as guides to their patients’ health, in agriculture, we rely on soil test results. Soil testing supports both the health and nutrient value of plants. A deficiency of one or two essential soil nutrients reduces not only yields but also the level of nutrients within plant tissues that will be ingested by humans or animals. Soil that is deficient in zinc, copper, iron, magnesium, calcium, etc. will produce plants that are equally deficient, which will have a direct effect on your health.
    If you have applied 10-10-10 fertilizer on your garden or lawn for many years, it is likely that your soil has too much phosphorus. That excess can, in turn, result in reduced crop yields and plants deficient in zinc, iron, copper and manganese. The excess phosphorus binds these nutrients, making them unavailable to the roots of plants.
    This is the problem farmers experience from repeated applications of chicken manure, which is rich in phosphorus. In that case, the excess phosphorus in the soil is making the soybeans or corn grown there deficient in essential elements. Humans or animals eating those grains will not get a nutritionally balanced diet.
    Too much phosphorus causes still more problems. When soil erodes and enters Bay waters, phosphorus attaches to clay particles. When these clay-laden soils penetrate silt fences and enter the Bay, the phosphorus is released, adding to the water’s nutrient-concentration problems.
    Another element, boron, is also secretly at work in your soil. If you are gardening in a sandy loam or loamy sand, boron deficiency is likely. Plants do not require much boron, but its deficiency affects yields and storage life. You have likely seen the result without recognizing it. The brown punky blotches you sometimes see beneath the skin of an apple tell you that the fruit was grown on boron-deficient soil.
    Without soil testing, you won’t know the invisible forces at work in your soil.
    I can now give you a choice of two laboratories for your soil testing:
    • A&L Eastern Agricultural Laboratory, now known as Waypoint: www.al-labs-eastern.com (804-743-9401; 7621 Whitepine Dr., Richmond, VA 23237).
    • AgroLab, Inc.: www.agrolab.us (302-566-6094; 101 Clukey Dr., Harrington, DE 19952). Request a soil-testing kit, including instructions on how to take qualitative soil samples.
    Include my e-mail address (dr.frgouin@gmail.com) on the information sheet to have results sent to me for interpretation. Include your own e-mail address as well so I can forward you my recommendations.
    Good recommendations depend on a good sample. To represent your current soil conditions, take at least five core samples to a depth of six inches in six different locations in your lawn or garden. Mix the core samples thoroughly in a clean container. Remove about a cup of soil for testing. Spread the sample on a clean piece of newsprint to dry overnight before mailing. On the form, identify what’s to grow in that area. Results are typically returned within a week.


Ask The Bay Gardener your questions at DR.FRGouin@gmail.com. Please include your name and address.

One of gardening’s incomparable pleasures



There is nothing like sneaking into the garden in mid to late July after the potato plants have finished flowering and stealing a few thin-skinned potatoes. If you hill your potatoes with compost in place of garden soil, you can harvest potatoes without disturbing the plant. At the final harvest, you get the added benefit of potatoes that are almost dirt-free.
    Freshly dug potatoes have a flavor all their own. Mashed, they are nice and fluffy; French-fried, they are always golden and absorb very little cooking oil; baked, they are outstandingly delicious. They bring all these advantages because they are nearly 100 percent starch. As their thin skin needs no peeling, they are packed with vitamins that concentrated immediately under the skin. If you like hash brown potatoes with onions, your garden can provide both because the long-day onions you plant this spring will be bulbing at about the same time you start taking potatoes from the plants.
    Hilling potatoes with immature yard-debris compost in place of garden soil has many advantages. First, it forces you to generate an abundance of compost because it takes a lot to hill potatoes. By the time the potato plants are two feet tall, you will have had to hill them at least three times. For a row 80 feet long, that’s at least five wheelbarrows full. Purchasing that much compost would cost you a pretty penny. Furthermore, the compost you purchase is finished and heavy to handle. Immature compost from the composting bin that you filled last fall has a large amount of partially decomposed leaves mixed with more fully decomposed materials, making it less dense and easy to transport and apply.
    Second, by hilling the potato plants with compost, you can easily push your hands in until you feel an edible potato. As long as you gently remove the potato from the rhizome, you do not retard the growth of the plant.
    Third, as immature compost does not absorb much water, even the smallest rain will penetrate down into the soil where most of the roots that feed the plants are located.
    Fourth, potato beetles do not appear to be as problematic on potatoes hilled with unfinished compost. Entomologists tell me that adult potato beetles are not good navigators. They have no problem taking off, but when it comes to landing, they often miss their target. Instead of flying back to the plant they missed, they walk on the soil. They appear not to like walking on rough surfaces such as unfinished compost. Thus, when hilling with unfinished compost, keep the leaves of the plants from touching the ground.
    There are many years I have not had to spray for beetles. A daily walk through the planting to remove the beetles by hand, dropping them into a container, is all that has been necessary.
    Fifth, by hilling with compost you have added to the organic matter of your garden soil. By rotating my potato planting every year, I manage to apply a uniform layer of compost over the entire garden every five years.
    All that and delicious young potatoes, too.


Ask The Bay Gardener your questions at DR.FRGouin@gmail.com. Please include your name and address.

How to control these and other web-builders

Those white webs expanding in the crotches of cherry, crabapple and Juneberry trees are made by eastern tent caterpillars. Last summer and early fall, the adults laid their eggs in these favorite trees. As the larvae emerge, they spin a web around the nest, giving it protection from the weather. In the evening, the larvae crawl out from under the web to feed on nearby tender young leaves. Just about the time the sun rises, they return to the web for protection. As the population of larvae increases and the larvae increase in size, so does the webbing of the nest.
    As long as the larvae remain under the protection of the web, they are protected from birds and the elements as well as from insecticidal sprays. You will never see birds feasting on these webs. If you poke your finger into one, you will see why birds do not bother them.
    “The defoliation usually does little damage to trees, and rarely do trees die from an infestation,” says Maryland Agriculture Secretary Joe Bartenfelder.
    The lack of damage is due to timing. Because the caterpillars hatch as soon as the young leaves unfurl in the spring, the tree has put little energy into the leaves and typically re-foliates in June, seemingly no worse for wear.
    Do not try to control the eastern tent caterpillar by torching the nests. Torching with a flaming kerosene-soaked rag tied to the end of a pole is not only dangerous but also causes permanent damage to the tree.
    The best method of control is to spray the foliage nearest the web with an organic pesticide such as Thurcide or Dipel. These pesticides contain the BT bacteria that kill the feeding larvae from the inside out. They are approved for use by organic gardeners. To obtain maximum effectiveness, apply in the evening to the foliage in the feeding area. A single application will provide protection for three to four days; it will take a few days before you see evidence of the treatment. The smaller the larvae, the better the control. As the larvae grow larger, they become more difficult to kill with BT.
    Use a fresh supply of these organic pesticides, not an unused portion from last year. Once the bottle is open, the effectiveness decreases with time. Unless you are going to be using them to control other pests in your garden, such as cabbage loopers, bagworms or corn-ear worms, purchase the smallest container possible.
    In mid to late summer, you’ll see similar webs on a wide variety of woody plants. These are created by the fall webworm. The same treatments can be used to control these pests. In July, you may also see webs on two-needle pines such as Virginia pine and mugo pine. To control the pine sawfly creating them, you’d need the hard pesticide Sevin.


Is My Compost Safe to Use?

Q I shredded some sunflowers in my composter this past fall. I forgot that they are like walnut trees and put out a mild toxin that can negatively affect other plants. Can I use this ­compost? Or should I just throw it out?

–Mike Morgan, Bowie

A The composting process destroys the enzymes that cause the allelopathic effect, so you can use your compost.


Ask Dr. Gouin your questions at DR.FRGouin@gmail.com. Please include your name and address.

Plants are survivors

The spring of 2016 will be remembered as a short spring and a very short summer followed by a short fall — all within four weeks between March and April. Those 70-degree days in mid March stimulated the vegetative buds in many woody ornamentals to swell, causing the winter bud scales to drop to the ground. This left the buds susceptible to damage by freezing temperatures.
    Some Bay Weekly readers have reported buds on their hydrangeas turning brown and drooping, which has never happened before. Others have reported that the new growth on their Euonymus shrubs is turning white and wilting. Others have reported that that frosty nights have caused their American hollies to develop yellow leaves that drop to the ground. They seem to forget that hollies lose their leaves in spring as they start to grow new leaves. The difference is that this year, the transition from old to new is occurring earlier than ­normal.  
    The peach crop will most likely be sparse this year because most of the trees were in full bloom when the frost hit. Once flower petals begin to unfurl, they lose their cold-hardiness. Late-blooming varieties will produce peaches because their flower buds were still closed at the time of the last frost.
    Early asparagus spears wilted to the ground in the section of the garden where I had tilled the soil to control weeds. Where the garden was not freshly tilled and the soil was firm, the early spears were not affected. The difference is due to the heat loss from the soil, which provides frost protection. Where the surface soil was loose, there was not sufficient heat retention to provide frost protection close to the ground. I have seen similar results in gardens where the asparagus beds are mulched. The mulch prevents heat loss from the ground, resulting in the early-rising spears vulnerable to frost.
    But plants are survivors. By the first of June, everything will just about look the same, regardless of late-frost damage.

Planting Schedule
    If you are anxious to get dirt under your fingernails, this is the time for planting potatoes, onions, cabbage, broccoli, lettuce, cabbage, Chinese cabbage, radishes, kohlrabi, cauliflower, spinach and bak-choi.
    Delay planting tomatoes, peppers, melons, squash and cucumbers until the second week in May. If you are using stakes or cages to grow your tomatoes, remember to spray them thoroughly with a 10 percent bleach solution before installing them. There is evidence that spores of blight on last year’s tomato plants can over-winter on the stakes and cages.


Ask The Bay Gardener your questions at DR.FRGouin@gmail.com. Please include your name and address.

Crowded bulbs are smaller bulbs and produce smaller flowers

As the trumpets of daffodil petals herald spring, we see clumps growing in roadside banks as well as in gardens. Pretty as they are, the flowers in those large clumps are not as large as those of single plants or smaller clumps. Crowded bulbs are smaller bulbs and thus produce smaller flowers due to a lower reserve of food.
    Professional gardeners dig up and thin out clumps of daffodils every five or six years. This practice allows them to not only maintain flower size but to also expand plantings.
    If you would like to lift and thin your bulbs, now is the time to take the first step. First, use a large plant label or planting stake with a weatherproof tag to mark the location of each clump to be dug, and identify its flower color.    After the foliage dies down to the ground, give the blubs a couple of more weeks to mature. Foliage will die more slowly in clumps growing under partial shade than those growing in full sun.
    To minimize damage to the bulbs, use a fork spade for digging and lifting out the bulbs. Start digging at least three or four inches away from the ring of dead foliage. Lift the bulbs and spread them on the ground to dry in the full sun for an hour or so. After the soil on the bulbs has dried, remove it by rubbing gently with your hands. Avoid damaging the tunic, the thin papery covering on the bulbs. Do not attempt to separate the bulbs from each other at this time.
    After harvesting, spread the bulbs on a flat surface in a well-ventilated room under cover to finish drying for a few weeks. Then place them in mesh bags or screen storage trays, and store them in a cool, dry place protected from rodents.
    In September, plant the bulbs where you want them to bloom next spring.


Is salt damage reversable?

Q Is there any way to compensate for winter salt damage to trees and ­bushes? Also affected is the grass strip ­paralleling the road.

–Farley Peters, Fairhaven

A Most of the damage caused by salt is due to salinity, which kills plant roots. If the sodium level in the soil is equal to or higher than that of potassium, then the damage is more likely related to nutrition. Have the soil tested to see if there is sufficient potassium.


Ask Dr. Gouin your questions at DR.FRGouin@gmail.com. Please include your name and address.

Grow a patch of rhubarb

My old friend Bill Burton and I once discussed eating freshly harvested rhubarb as kids during hot summer days in New England, where every home had a rhubarb patch in the backyard. Bill raved about his mother’s rhubarb-custard pie, while I raved about my mother’s strawberry-rhubarb pie. I can still picture myself sitting on the back stairs of our home with a fist full of sugar in my left hand and a freshly harvested stalk of rhubarb in my right. Before each bite, I would dredge the base of the rhubarb stem in the sugar.
    Those were the days.
    Rhubarb is a vegetable, not a fruit, although we tend to limit its use to making desserts. One of the great features of rhubarb is that it can be blended with other fruit such as strawberries, blueberries, apples, pears and apricots as the rhubarb absorbs the taste of the fruit. In other words, you can make a tasty blueberry pie using only one cup of blueberries and two cups of chopped rhubarb.
    Rhubarb grows best in well-drained soil in full sun. It can tolerate partial shade, but it will produce spindly stems. Since you consume only the stem, the fleshier the stem the better. Never eat the leaves because they contain oxalic acid, which will cause swelling of the tongue.
    I have seldom seen rhubarb sold in a garden center, though it is commonly listed in seed catalogs. If you order rhubarb for your garden, you will receive in the mail what appears to be a dried-up brown stub. For best results, place it in a cup of water for five days before planting.
    There are various clones of rhubarb with stems ranging from green to various shades of green to red and red only. There is even a clone labeled Strawberry-rhubarb. I can assure you that it does not have a strawberry flavor.
    Rhubarb likes mildly acid soil with a moderate amount of organic matter. When planting rhubarb, I dig a hole the size of a half-bushel basket and add two to three shovels-full of compost and a handful of agricultural limestone, then mix thoroughly.
    Allow the rhubarb to grow without harvesting for at least two years before pulling your first stems. During your first harvest on the third year of growth, remove no more than half of the stems at any one time and allow one month between harvests.
    If you see a flower head develop in the center of the clump, remove it with a sharp knife two to three inches from the ground. Allowing the plant to produce seeds during the first three years of growth will weaken the clump.
    Never try growing rhubarb in a large container or in a raised bed. The roots are sensitive to high temperatures, which will cause the plant to die in mid-summer as rooting media rises in above-ground containers or beds.


Ask The Bay Gardener your questions at DR.FRGouin@gmail.com. Please include your name and address.

A successful harvest depends on the right bulbs for our hours of light

Onions are good for your health, and generally they are easy to grow. Let me give you some advice on growing them successfully.
    Plant onion sets and you’ll harvest only green onions. Most sets you buy are short-day onions, which produce bulbs only when grown during the winter months with 10 daylight hours or less. Planted in the spring, as daylight hours grow longer, they produce only onion tails, your green onions.
    To grow onion bulbs, you must buy either long-day or intermediate, aka day-neutral, onions. They are shipped in bundles of 75 or more seedlings. Unless you are familiar with a particular variety, I suggest planting two or more varieties. Harvesting will be easier if you keep each separate in the garden, as they’ll mature at different times.
    Onions perform best in high organic soils with a nearly neutral pH.
    The spacing between onion plants is based on the mature bulb size. The most desirable bulb size for kitchen use is one and a half to two and a half inches. For those sizes, use a four-by-four-inch spacing. Bermuda and Walla Walla-size onions need more space; plant them in six-by-six-inch spacing. Those spacings allow room for the bulbs to grow and for you to cultivate between the plants without damaging the bulbs.
    Fertilize two to three weeks after planting and monthly thereafter. Don’t let the soil dry out; onions have a very limited root system, and there is a high population of plants in a limited area.
    Neck rot of onions can be a serious storage problem. Avoid it by knocking the foliage to the ground just as the bulbs begin to mature in late July and August, depending on the variety. Do so as soon as the color of the foliage begins to fade and the tops of the onion tails start turning brown. I use the back of a garden rake.
    Leeks want four-by-four-inch spacing as they do not produce bulbs but do produce thick stems. They have the same growing requirements as onions.
    Garlic planted last fall is now in need of fertilizer. Like onions, garlic plants have a limited root system and respond well to fertilizer and water. Remove the flower buds as they begin to form, mid- to late June, depending on variety. If the garlic plants flower and produce seeds, both bulb and cloves will be smaller. For large cloves of elephant garlic, early removal of the flower stem is doubly important.


Ask The Bay Gardener your questions at DR.FRGouin@gmail.com. Please include your name and address.

 

Many will bloom again in your garden, but some are destined for compost

If you received Easter plants, you’ll be able to plant some of them in the garden to enjoy again next year. Others are best recycled by composting them.
    Replant: Potted tulips, daffodils, hyacinths and crocuses can be planted in the flower garden. Don’t wait until the plants have died back to the ground. As soon as the flower petals have dropped, transplant them by digging a hole 10 to 12 inches deep, place a couple inches of compost in the bottom of the hole and mix with the existing soil. Carefully remove the root-ball from the container, loosen the layer of roots at the bottom of the root ball and place in the hole. The bottom of the root ball should be at least eight inches below the surface of the soil. Blend one-third by volume compost with the soil removed when digging the hole and carefully backfill around the stems. The bottom of the leaves of the plants should be just above the soil line.
    Many forced Easter lilies are not very cold-hardy. Since the frost seldom penetrates more than six inches in Southern Maryland, the bulbs’ lack of cold-hardiness can be solved by planting them 10 to 12 inches deep. Move the plants outdoors as soon as possible and keep them watered. For maximum effect, plant the bulbs in groups spaced 10 inches apart. If you only have one Easter lily, plant it as described above. If you have many (note that your church likely discards its lilies as soon as they have finished blooming), plant them in trenches. Dig a trench six inches wide and 12 inches deep and blend compost into the bottom soil. Carefully remove the plants from their pots and loosen the bottom roots. Space the plants in the trenches and backfill with soil amended with compost. Don’t worry about covering the bottom leaves with soil. What is important is that the bulbs be planted deep enough that the soil protects them from freezing. Your outdoors Easter lilies will flower next year but not in time for Easter.
    Compost: If you received potted hydrangeas, I highly recommend that you add them to the compost pile. The cultivar of hydrangea used in greenhouses does not have cold-hardy flower buds. If planted outdoors, it will produce attractive plants, but unless we have an extremely mild winter, it will not flower. Hydrangeas for outdoor landscaping are different cultivars.


Ask The Bay Gardener your questions at DR.FRGouin@gmail.com. Please include your name and address.

In spring, feed your soil — not your grass

Warm-season grasses, including Zoysia and Bermuda grass, should be banned from Chesapeake lawns. They cause nothing but problems. Lawns planted with these grasses have to be fed monthly May through August with high-nitrogen fertilizers. They must be sprayed yearly with restricted-use pesticides to control billbugs and other insects. They must be mowed close to the ground, so they often become infested with weeds, which requires the frequent use of herbicides. The clippings must be collected and the lawn dethatched.
    Warm-season grasses are green during the summer months and yellowish-brown in fall and winter. Some homeowners go so far as to spray them with Greenzite in late fall to make them more attractive.
    For the best Chesapeake country lawns, plant bluegrass and fescue.
    Bay soil is better suited for growing cranberries and blueberries than for grass. If you want a lush weed-free lawn next year, late April and early May is when to take action.
    If you haven’t had your soil tested in the past five years, it is likely that you will have to lime your soil. Soil in the Bay area tends to be very acidic. When you apply lawn fertilizers on acid soils, the chances are great that much of the nutrients from the fertilizers will either be washed into the Bay or into the groundwater. If you want your lawn to be dark green and dense, this is the time to apply limestone — not fertilizer.
    Lawn grasses grow best on soils that are only moderately acid. It is not uncommon to find soils in the Bay area having a pH of 4.2 to 4.5. Since a pH of 7 is neutral, this means that such soils are very acid and would be ideal for growing cranberries and blueberries — if we had the proper climatic conditions.
    By applying limestone now, you’ll neutralize your soil, bringing it closer to the ideal pH for growing lawns, between 6.0 and 6.5. In this pH range, all of the nutrients essential for good plant growth are available to the roots of the grasses. In turn, fertilizers you may apply in fall — which is the best time to fertilize bluegrass and fescue lawns — will be effectively utilized by the grasses.
    Soil testing is the only sure way to determine the amount and kind of limestone to apply. If you don’t want to take the time to have your soil tested, then apply between 50 and 80 pounds of dolomitic limestone per 1,000 square feet. Do not use hydrated or high-calcium limestone, since most of our soils are deficient in magnesium, and dolomitic limestone contains magnesium.
    If you live near the Bay, you should not be using weed killers. Matter of fact, weed killers for lawns should be outlawed. Not only are they unnecessary and expensive, they contribute to the pollution of the Bay.
    Working with herbicides almost continuously since 1958, I have respect for them and their responsible use. But the application of weed-and-feed fertilizers is an irresponsible use of both herbicides and fertilizers.
    The time to apply a pre-emergent herbicide to control crabgrass, dandelions and other broadleaf weeds is within two to three weeks following petal drop of forsythia: no later than early May in the Bay area. Applying weed-and-feed fertilizer earlier means that by the time the crabgrass starts to germinate, the pre-emergent herbicide will have become ineffective.
    Applying fertilizer to a bluegrass or fescue lawn late in the spring means that you will be promoting soft, succulent growth that will be susceptible to disease. Then you will have to purchase a fungicide to control the diseases you caused by applying the fertilizer too late in the spring.
    If only a few weeds are growing in your lawn, why apply a weed-and-feed fertilizer over the entire lawn? I have yet to see a decent lawn that needs a weed-and-feed fertilizer treatment.
    If the lawn is nothing but weeds, it is time to start over in August or September. No amount of weed-and-feed fertilizer can reclaim a neglected lawn.

To Test Your Soil
    Send soil samples for testing to Waypoint Analytical (formerly A&L) in Richmond. Full instructions for testing are online: www.soilandplantlaboratory.com/services/soilsampling.aspx.
    If your soil is a sandy loam or loamy sand, have it tested for all trace elements, especially boron (B). However, if your soil is a loam, silt or clay loam, the general soil test will suffice.
    If you have been growing multiple crops each year, you most likely will need to apply limestone. If you want me to make recommendations, don’t specify a crop (a savings of $3 to $5) and include my email so I’ll get your results: dr.frgouin@gmail.com.


Ask The Bay Gardener your questions at DR.FRGouin@gmail.com. Please include your name and address.