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Features (Gardening)

Help these fruit trees recover from two bad winters

The winter of 2013-’14 killed the stems of most of the figs in southern Maryland. However the roots were still very much alive and generated an abundance of new stems from the ground. The robust roots produced stems that were able to produce a few figs. But most stems produced no fruit. They would have this year, except for another killing winter this past year.
    At the northernmost range for growing figs, we have to face the fact that extremely cold winters can mean no fruit.
    Don’t expect to harvest any figs this summer. If the winter of 2015-’16 is equally severe, it is unlikely that roots will be able to generate new growth.
    If your fig plants were killed back again overwinter, by now you should see an abundance of new sprouts originating from the roots. Help your fig recover by pruning out dead stems as close to the ground as possible. To encourage the development of strong sturdy stems, break off all weak, thin stems growing from the roots. It’s better to break off the stem than to prune it. If you cut away the stem with pruners, chances are a vegetative bud will develop in the axis of the stump of the stem and the root, resulting in the growth of a new stem. Allow at least ___ feet between the best-growing stems.
    To break a stem from the roots, I use a four-inch-wide board that’s three to four feet long. I place the end of the board near the weak stem and kick it. This causes the weak stem to shear from the roots, making it highly unlikely that another stem will grow in the same area. Do this while the young stems are green. The roots will be pushing up new stems, so you’ll have to repeat at least twice monthly to remove the previous weeks’ spindly stems.
    Once the stems have started to grow, they will benefit from an application of fertilizer at the rate of approximately one pound per 100 square feet. I generally do not recommend fertilizing figs because it makes them grow too tall, producing less harvestable fruit.
    Plant fig trees on a slope facing south or against the south wall of a building to provide maximum winter protection. I have all of my figs growing again the south wall of a brick house. This exposure provides more warmth from reflective heat from the building and early warming of the soil, especially when the ground is not covered with snow. The soil in a slope facing south always warms sooner than the soil on a slope facing any other direction.


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

It’s harvest time

If you planted garlic last fall, the tails should be at least 24 inches tall, and you should be seeing the tops of the bulbs by now.
    If you, like me, planted elephant garlic, flower heads will now be developing at the end of its tall cylindrical stem.
    Most German, Italian and other soft-neck garlics do not flower. 
    On hard-neck garlic, look for swelling and a pale ring forming near the tip. As soon as the swelling appears, remove the flower head using a sharp knife. A friend removed the flower buds by giving the tail a quick snap. In so doing, he pulled the bulbs partially out of the ground, causing his elephant garlic to produce only small cloves. The cloves and entire bulbs were no larger than those of the Italian white garlic growing next to the elephant garlic.
    As soon as the foliage starts turning yellow-green, push it to the ground using the back of a rake or by dragging a log or timber over the plants. This will help prevent neck rot, which can result in substantial loss in storage.
    Whether hard-neck elephant or German, Italian and other soft-neck varieties, garlic can be harvested for cooking at any time after the stems have fully developed. Cloves will be smaller when harvested early.
    Garlic will be fully developed as soon as the foliage starts turning from yellow to brown. If you intend to store some, delay harvesting until most of the foliage has turned brown.
    Braid soft-necked garlic and hang for drying. It is impossible to braid hard-neck garlic, so it is best to tie the stalks in bundles of three and create a chain of them to hang for drying. I hang my garlic in a shady area in an open garage so air can circulate freely. Allow three or four weeks for drying before placing them in storage.
    All garlics are short-day plants, which is why they have to be planted in the fall when they can be exposed to short-light days after initiating growth. If you wait to plant garlic in the spring, you won’t harvest much of a crop.
    Poor crops are why this will be the last year I try growing short-day onions. Over three years, I’ve found the harvest unworthy of the expense, time and effort. Last fall, I planted some in an outdoor bed, some in a cold frame and some in my greenhouse. Only the plants in the cold frame produced decent-sized bulbs.
    Our winters are much too cold for growing short-day onions outdoors without some protection. A deep cold frame or tunnel is required. Nor do short-day onions perform well in a heated greenhouse. My recommendation is to grow long-day or intermediate onions, planting in the spring and harvesting in August.
    If you planted either this spring, the tails should be at least 12 inches long and growing.
    Of the long-day onions, I find Copra to be the best keeper. Our crop of Copra harvested last August lasted through March. Candy and Superstar are sweet and mild but not good keepers. Big Daddy is the best variety for onion rings.
    As with garlic, push the foliage to the ground to prevent neck-rot and help your crop store better. After harvest, braid the onions and hang — mine are in the garage with the garlic — until the weather turns cold in the fall.


Neck Rot Strikes

Help please! The stems of my garlic and of a friend’s have fallen this year and are lying limp on the ground.

–Bill Lambrecht, Fairhaven

 

The garlic should have been harvested as soon as the stems started turning yellow green. It has a bad case of neck rot. Harvest the garlic ASAP and separate the cloves from each bulb, dry them at room temperature and store them in the top shelf of the fridge.


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

There are better ways than mulch

Do you think the only method of controlling weeds is mulching?
    If so, you’re likely to add another layer of mulch every time you see weeds growing through the last layer. From there on, mulching becomes a habit.
    Mulches control weeds by suffocation and by shading the soil, thus denying the weed seeds the red waves of sunlight. The red wave band of the sun’s spectrum stimulates weed seeds to ­germinate.
    But thick layers of mulch also prevent oxygen, necessary for good plant root growth, from entering the soil. Thick layers of mulch also absorb the first quarter-inch of rain or irrigation, keeping it from reaching the soil.
    Never apply a layer more than an inch or two deep each per year. Before applying a new layer, always incorporate the previous year’s mulch into the surface soil. Where azaleas, rhododendrons and mountain laurels are growing, it is best to remove the old layer. Pine bark is the exception; incorporating it with a steel rake may be adequate.
    If the color of the old mulch is not satisfactory, consider spraying it with liquid mulch. Liquid mulches in the same dies used to color the raw wood chips are available from suppliers such as A.M. Leonard.
    If weeds are a severe problem, consider covering the ground with landscape fabric before applying mulch. However, if Bermuda grass, pigweed or nutsedge are present, these must be irradiated before applying the landscape fabric because they will grow through the fabric, making it impossible to remove.
    Avoid using black plastic around shallow-rooted plants. Unlike landscape fabric, plastic inhibits the movement of oxygen into the soil.
    Small weeds in the landscape can be controlled by spraying with horticultural vinegar. Horticultural vinegar contains 20 percent acetic acid and will kill weeds up to about three inches tall. It is also available from A.M. Leonard. If the acetic acid accidently comes in contact with the foliage of desirable perennials, it will not cause any permanent damage.
    Before you use an herbicide, know how it works. Preen, for example, is a preemergent herbicide you can use only on clean cultivated soil. As it contains only fluoride, it kills primarily germinating seeds of grass and only a few broadleaf weeds. So it is safe to use near and around ornamental plants, but it is effective for no more than six weeks. Always follow manufacturer’s recommendations when applying any herbicide.


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

What’s good and bad for what

Never use colored mulches near annuals, shallow-rooted trees and shrubs or herbaceous perennials. These mulches are made using raw wood that serve as a source of food for microorganisms once it comes in contact with the ground. Microorganisms are better able to absorb nutrients in wood than are the roots of plants. As a result of the competition, plants — including weeds — starve and die. 
    Use colored mulches only around well-established deep-rooted trees and shrubs, for making pathways, sitting areas and playgrounds.
    Use hardwood bark mulches with caution.
    Unlike pine mulches, hardwood bark mulches contain up to 60 percent cellulose, which means they will decompose and rob nutrients from plants. They will also raise the pH of soils, making them less acidic. Repeated applications of hardwood bark can also result in the accumulation of manganese. When this occurs, the roots of the plants lose their ability to absorb iron and plant growth declines. Over the years I have seen numerous instances where the manganese and pH levels in the soil were so high that the only solution was total replacement of the soil.
    As you shop for pine bark mulch, be aware that not all bark mulches contain 100 percent bark. Some are made by blending one part pine bark and two parts wood chips. These blends are kept moist and turned periodically until the entire mass turns brown like bark.
    The truth is revealed if a piece of its wood reveals a yellow to light-brown center when broken. Once applied, fake bark mulches are more easily identified: After they have weathered a few weeks, the tannin-treated raw wood begins to lose its dark brown color.
    If that’s what you’ve got, the brown-colored raw wood will feed microorganisms, not plants.
    I was once called to investigate problems resulting from a mulch sale sponsored by a grocery chain. A large trailer load of double-shredded hardwood bark mulch had been trucked in and sold at cost. Buyers were immediately returning the mulch, complaining that it was killing their plants instantly.  Inspecting the load of mulch remaining in the trailer, I found it contained wood alcohol. I proved the presence of alcohol by cutting open a bag and throwing in a lighted match. The mulch immediately caught on fire. The mulch had been bagged while it was composting under anaerobic conditions, resulting in the formation of wood alcohol.
    Marble chips should not be used around plants that require acid soils. Marble chips are essentially chunks of limestone rich in calcium oxide, which will result in making the soil less acidic and eventually alkaline. That will be the death of acid-loving plants such as azaleas, rhododendrons, mountain laurels, andromeda, skimmia and Japanese hollies.
    Marble chips are safe around alkaline-preferring plants such as junipers, yews, pines, spruce and cherry laurel.
    Avoid using bluestone. I have seen numerous cases where plants have been killed after bluestone mulching. Like marble chips, bluestone contains high levels of calcium oxide. It may also contain metal contaminants, including nickel. The symptoms often go undetected for several years, by which time the damage is irreversible.


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

It’s not there just to look pretty

Good mulch should be dark brown, persist for at least one growing season, be compatible with all the plants in the landscape and control weeds by suffocation only. Superb mulch does all that plus providing slow-release nutrients to feed the plants it is mulching.
    Mother Nature provides us with an abundance of mulches every fall. Fallen leaves and pine needles are excellent mulches satisfying every standard except being dark brown.  I have never purchased a bag of mulch in my life. Leaves are my mulch. When they decompose, nutrients are released into the soil, thus feeding the roots of mulched plants.
    Bark mulches do not contain any of the major nutrients used by plants except for calcium. But bark can contain essential trace elements, such as manganese, that can accumulate in the soil and cause problems. Thus it is important to choose mulch that is compatible with the species of plants being mulched.
     If you insist on purchasing brown mulch, I recommend pure pine, spruce or fir bark mulches. These contain 90 to 100 percent lignins, a source of carbon not easily digested by microorganisms. Thus they do not decompose readily and last on the surface of the ground one to two growing seasons. These mulches also contain polyflavanoids, which are beneficial because they help make essential trace elements available to the roots.
    Pine bark is available as nuggets, ground or as pine fines. The nuggets and ground mulches are the most preferred. Pine fines are generally only recommended as a soil amendment to increase the organic matter and help in lowering the pH of soils. Pine mulches are acidic in nature.
    Pine needles can be used as mulch but have a limited life, lasting only two to three months.
    Pea stone makes good mulch providing it is laid over landscape fabric. Brick chips, volcano slag or crushed granite are also usable mulches. But because of their density, they will sink into the soil unless they are placed over landscape fabric. 
    In the vegetable garden, straw — not hay — works as mulch. Even newspapers can be used, applied in 10 to 15 layers and soaked with water immediately to stop them from being blown away. I use shredded paper because it is easier to spread and, once soaked with water, remains in place better than sheets of newspaper. You need not worry about the ink because most black ink is made from soy while the colored inks are organic. I would prefer the old zinc ink because most of our soils here in the East are low to deficient in zinc, a mineral important in our diet.
    Shredded cardboard also makes good mulch. The advantage of using straw, newspapers, shredded paper and cardboard is rapid decomposition without creating nutrient stress. As they are opaque, they control weeds by the shade they create.
    Black plastic and landscape fabric also make good mulch. Black plastic mulches prevent the loss of water by evaporation. But these must be removed at the end of the growing season. Landscape fabric has another drawback in that weeds such as Bermuda grass, pig weed and nut sedge can grow through the fabric, making it impossible to pull them without damaging the fabric. Removing the fabric at the end of the season is also harder because of weeds that have grown through it.
    Next week, I’ll give you more reasons to avoid other mulches.


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

Oh the harm it causes!

In 1976, I wrote “Over-Mulching, A National Disaster” for a national trade journal. Nasty letters came from as far as Oregon and California. Forty years later, over-mulching has become a monkey-see-monkey-do calamity.
     Earlier this spring, I spent several days diagnosing plant problems for several landscape architects. In all but one, the problems were caused by excessive use of nutrient-robbing mulches.
    In several instances, well-established plantings of pachysandra were being suffocated by excessive mulch or starved by mulches containing raw wood. Where raw wood was applied around pachysandra, the plants were yellow green and the vegetation sparse. In the areas where four inches or more of mulch was applied, the pachysandra was dead and the stems rotten. 
    In one landscape, several hundreds of square feet of what was once a well established planting of English ivy was killed after having been mulched with Big Red. About three inches had been applied last year, follow by another application this year. I am frequently asked to recommend an herbicide for killing English ivy; from now on I will recommend a heavy mulching with Big Red. Guaranteed to give 100 percent control, organically.
    I saw azaleas with sparse distribution of small purple leaves and struggling in what appeared to be two to four inches of shredded hardwood bark. Soil tests indicated in excess of 300 pounds of manganese. Any level in excess of 80 pounds per acre is considered toxic to the roots of plants. It’s clear from the soil test results that shredded hardwood bark had been applied repeatedly for several years. Since the property owner had hired several yard maintenance firms over the years, she was not aware of what kind of mulch had been applied.
    In one yard I examined a large planting of boxwood with severe symptoms of decline. Digging around the base of the plants, I saw that they had been mulched several times. Over the years I have seen numerous once-healthy and hardy boxwoods killed by mulch. Boxwoods are shallow-rooted plants and should never be mulched. They are drought tolerant, and enzymes emitted by the roots and leaves prevent many weed species from growing around them.
    Most of the landscape maintenance companies were blaming poor drainage for decline or death. However, as I walked on the lawns adjoining these plantings and in the plantings, I saw and felt no symptoms of poor drainage. I augured holes in these areas and found the soil to be well drained.
    The only landscape where I did not see mulch problems was in a yard where water coming from a newly installed copper roof had flowed. Here, the decline in growth and the loss of plants was due to copper toxicity. I could easily follow the flow of water from the downspouts and areas where the water pooled. The solution to this problem was to divert the water away from the plants until the surface of the copper sheeting oxidizes to a brown or gray-green color.
    More on mulch next week …


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

Telltale signs, and how to fight back

That black and white bird with a red cap and yellow belly is not a traditional woodpecker looking for bugs hiding beneath bark. At work making numerous holes all in a circle around the trunk of your tree is a yellow-bellied sapsucker, who then sucks sap from those wounds.
    In early spring, sap migrates to the phloem, the region just beneath the bark, and these birds are eager to suck those juices. Warm days and cool nights make the sap flow hard and furious, and the sapsuckers know it.  
    Sapsucker damage is easy to identify because the birds make one-half-inch diameter holes that penetrate through the bark into the cambium region. The holes are one-half to an inch apart and circle the trunk, starting from about eight feet above the ground up to where the diameter of the trunk is about six inches. Sapsuckers generally do most of their damage before sunrise and in the evening.
     They generally attack smooth bark trees such as magnolia, maple, cherry, apple, crab apple and ash. But I’ve also seen their telltale signs on pine and cedar. The damage they do can be fatal to some species. I’ve seen a southern magnolia so severely damaged that it had to be cut down.
    Why sapsuckers attack some trees more than others is not known. I have frequently seen two southern magnolia growing side by side, one showing severe damage while the other showed no damage.
    It is not uncommon to see hummingbirds feeding on the sap oozing from the holes as well as bees and wasps when the sapsuckers are feeding in the summer.
    Since sapsuckers tend to be skittish, the most effective remedy is to suspend shiny objects to the branches of trees being attacked. Cut 18-inch-long strips of foil six inches wide; twist the foil into long spiral tubes and tie the streamers loosely on branches with cotton string 10 inches to a foot away from the trunk. Space the foil strips two to three feet apart around the trunk. Use cotton string; if you forget to remove it, the cotton will decompose and fall to the ground. Wire or nylon could girdle the branches as they grow larger in diameter.


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

How to plant spring’s flagrant bloomer and its similars

As you continue your spring planting and transplanting, remember that many popular species perform best in acid soils. Among them are the now-blooming beauties azalea, rhododendron, mountain laurel, andromeda, Japanese hollies, deciduous hollies and blueberries. Oak and sweetgum trees also like acid soils.
    The best time to transplant these species is early spring and, even better, fall, when they’ve stopped growing new stems and leaves and are starting to generate and elongate roots.
    Pruning is best done just after blooming, but never on new transplants.
    Success in transplanting these species can be guaranteed if you follow the following guidelines.
    1. Know the Ph of your soil before planting. I rely on A&L Eastern Agricultural Laboratories in Richmond for all of my soil testing. Each soil test should be made from a composite of five or more core samples. Find directions at al-labs-eastern.com.
    2. Select a spot where the soil is well drained. None of these species will grow in poorly drained soils.
    3. All of these plants — except the trees — are shallow-rooted. The depth of the planting hole should not exceed 90 percent of the height of the root ball. In other words, 10 percent of the root ball should be above grade.
    4.  Add one-third to one-half compost by volume to the soil you removed when digging the hole. Do not bring in imported soil.
    5. Acid soils are generally low in calcium. Incorporate one rounded tablespoon of gypsum (calcium sulfate) to the compost-amended soil and mix thoroughly.
    6. If roots are tightly meshed around the outside edge of the root-ball after you remove it form the container, take a sharp knife and slash the roots at least one inch deep from top to the bottom of the root ball at three- to four-inch intervals around the entire root ball. Cutting the roots hastens root growth into the new soil.
    7. Water the plant well, even if it is raining, and repeat watering at four- to five-day intervals. Never water plants daily.


Is Your Soil Well Drained?

    To test drainage, dig a hole about a foot deep. Fill with water. Fill it again (some sources say immediately; some say the next day).
    Measure the depth with a ruler. In 15 minutes, measure again. How many inches has it dropped? Multiply by four to determine drainage per hour.
    Below one inch is poor drainage; over six is excessive. Anything in between is good drainage.


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

Fruiting plants need feeding

As you move tomato plants into your garden, here’s some advice to help improve your harvest.
    First, limit the amount of fertilizer and compost you apply when you transplant your tomato plants. Applying too much high-nitrogen fertilizer or high-nitrogen compost will produce extra-large plants and few late tomatoes.
    It’s in the production cycle that tomatoes need nitrogen.
    A fruiting plant must absorb nutrients sufficient not only to produce fruit but also to continue growing, producing more foliage, flowers and fruit. In other words, a mature tomato plant is much like a pregnant woman, eating for two to remain healthy and produce healthy offspring.
    That’s when the tomato plant is most nutritional needy, too. And that’s when early blight strikes.
    For a decade I have been studying methods of preventing early blight. Since 2009, I have had no early blight symptoms. I attribute that success to keeping my tomato plants nutritionally happy. Nitrogen is the key to a plant’s nutritional health.
    Nitrogen passes to upper-growing points or fruit from older leaves. Losing nitrogen makes those leaves susceptible to blight-causing microorganisms. If you supply tomato plants with sufficient nitrogen for the bottom leaves to remain strong and healthy, they are less likely to succumb to infection.
    Thus for the past five years, I’ve scattered a rounded tablespoon of calcium nitrate 15.5-0-0 around the base of each plant as soon as I see the first cluster of tomatoes form. During the growing season, I watch the bottom leaves of the plants closely. When those leaves start to turn yellow-green, I make a repeat application of calcium nitrate. Generally only two applications are needed per growing season.
    I selected calcium nitrate because mature plants absorb nitrate nitrogen more efficiently than they do other sources of nitrogen. Plus, the calcium in calcium nitrate helps build stronger cell walls and prevent blossom-end rot. There is lime in the soil, but the calcium in lime is only four percent soluble while the calcium in calcium nitrate is 100 percent available. Calcium is as important in plants for making strong cell walls as it is in humans and animals in making strong bones and teeth.
    If you are an organic gardener, apply at least two inches of compost around tomato plants as soon as you see the first flowers. Lobster waste or crab waste compost has the highest levels of calcium of all composted products available. Irrigate through the compost.


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

Prune buddleia, forsythia, weigela and privet with a heavy hand

To rejuvenate, some plants must have their stems pruned near the ground. The plants I’m describing each have a large root system, so the crowns will send up numerous new stems.  
    The butterfly bush (buddleia), for example, should have all its branches cut down to within inches of the ground every year in early spring. Severe spring pruning encourages the development of strong stems that will flower more profusely. I use a chainsaw to prune my buddleia at the beginning of March, which encourages the plant to flower sooner.
    Forsythia needs proper annual pruning. I make it a habit to prune one-third of the branches on my forsythia plants every year as soon as the petals fall. I start by removing the older stems with gray bark. I then remove all branches originating from the base that are smaller than a pencil in diameter as well as branches that are arching toward the ground. If you allow arching branches to touch the ground, they will root, and before you know it your mother plant will have produced daughter plants, and soon you will have more forsythia plants than you know what to do with. Forsythia grown without pruning will often die because of over-crowding of the branches.
    If you’ve fallen behind on the job, prune both species close to the ground as soon as most of the flower petals have fallen. If you prune now, new vigorous stems will emerge from the roots within a few weeks. Allow these stems to grow all summer long without further pruning. If the plants are in good condition, the new stems will grow to a height of five to six feet by mid July, and their bark will be brownish-yellow.
    Weigela also blooms better if one-third of old branches are cut out each year. Use the same approach as described for forsythia, removing the biggest woody branches. Shaped forsythia plants look awful, but weigela can be pruned for size, branch by branch as far back as one-third. Cut them back to a point where two branches meet. Untended weigela can take hacking, cutting all branches back to about four inches above ground level.
    Privet hedges that are old or have not been properly shaped often lose their bottom branches and leaves, making them appear top-heavy. Such hedges can be rejuvenated by simply cutting all of the stems very close to the ground and allowing new young stems to grow. The earlier in spring you prune them the better.
    The training of a new hedge begins as soon as the majority of the stems have grown 12 to 16 inches. To build a uniform hedge, pull a string the length of the hedge 10 inches above the ground, and prune away all stems that are above the string. Repeat after the new stems have grown another 12 to 16 inches, this time cutting them back to 20 inches above the ground. Continue until the hedge has achieved the desired height.
    To retain foliage from top to bottom, always shape the hedge so that the top is narrower than the bottom.  If you allow the top of the hedge to grow wider than the bottom, the top will shade the lower branches, which will lose their leaves.