Contact: Leslie Johnson
EAST LANSING, Michigan -- Outdoor gardening chores may be on hold in winter, but the questions never stop! Extension specialists at Michigan State University answer timely queries on vegetable gardening, landscape ornamentals, houseplants and related topics.
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ANR Communications Contact: L. Johnson or M. McLellan
MICHIGAN STATE UNIVERSITY Telephone: 517-432-1555 or 353-3774
East Lansing, MI 48824-1039
EAST LANSING, Michigan -- Cold temperatures, drying sun and wind, road salt, and snow and ice can take a toll on landscape plants. Homeowners can choose plants adapted to the growing conditions in their yards, maintain them properly and even take steps to protect them, but injury may still occur.
Mary McLellan, Extension Master Gardener program coordinator at Michigan State University, says winter injury to tender tissues can occur any time the temperature drops below freezing. Late-season fertilization or mild weather and fall rains that keep woody plants actively growing can dispose them to freezing injury when the temperature drops.
Likewise, unusually warm weather in early spring can cause plants to break dormancy and begin to grow, leaving them susceptible to damage by a spring cold snap.
Plants that become fully dormant in the fall have a built-in ability to withstand temperatures down to a certain level, McLellan explains. This is the basis of the U.S. Department of Agriculture’s hardiness zones, those maps in the plant catalogs that divide the country into zones where various plants can be expected to survive a normal winter -- or not.
"A good strategy when selecting plants is to choose those that are hardy in your zone or the next one north," she suggests. "You may get away with plants from warmer zones, especially if you’re blessed with a series of mild winters or you plant in a protected area, but the odds are that you’ll lose them to cold injury sooner or later."
In evergreen plants, winter injury to foliage is common. Bright sun and drying winter wind remove moisture from foliage that the plant’s roots cannot replace from frozen soil. The result is brown foliage in the spring.
"Brown needle tips in pines are a common sign of this drying injury," McLellan observes. "As long as new growth comes in healthy and green, the plant is probably okay, even though the brown needles will stay brown."
Brown evergreens that are producing green growth may not look too good for a while, but they will probably recover. But if needles -- especially new ones -- are falling off in the spring, the plant may have a serious problem, she notes. Unlike deciduous trees, which can replace new leaves, evergreens are unlikely to survive being defoliated.
Fall needle drop is normal, she notes. Though the plants stay green overall, individual needles don’t hang around forever.
Sometimes evergreens appear to have survived being flattened by a heavy load of snow or ice only to die later in the summer. The cause is damage to the plant’s vascular system, which carries nutrients produced in the foliage and water taken up by the roots. Severe damage kills the plants by starving the roots.
A common problem of smooth-barked deciduous trees is called frost crack or southwest disease. Both are misnomers -- frost crack doesn’t have anything to do with frost, though the bark does split and crack open; and southwest disease isn’t a disease.
"Frost crack occurs when the sun warms the tree’s bark, which expands," McLellan explains. "As night approaches, the outer bark cools and shrinks faster than the inner tissues. Finally the outer bark splits."
The crack poses no particular problem to the tree, but it can open the trunk to infection by disease organisms or attack by insects, she points out.
Planting hardy plants, maintaining them with a regular program of watering and fertilizing, pruning to remove poorly placed branches and dead or diseased wood, shading smooth-barked trees on the southwest side, and protecting evergreens against sun, wind and salt spray with burlap or canvas screens, can go a long way toward reducing problems with winter injury, McLellan sums up.
"When winter injury does occur on deciduous plants, don’t be too quick to remove them," she suggests. "A plant that doesn’t leaf out in the spring isn’t necessarily dead -- it may have suffered frost injury to leaf and flower buds. Secondary buds will probably open later."
On the other hand, a thoroughly brown evergreen that looks dead probably is dead, and no amount of waiting and hoping is likely to bring it back to life.
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ANR Communications Contact: L. Johnson or M. McLellan
MICHIGAN STATE UNIVERSITY Telephone: 517-432-1555 or 353-3774
East Lansing, MI 48824-1039
EAST LANSING, Michigan -- Someone asks what you’re planting in your vegetable garden this year and you yawn and say, "Ah, the same old stuff."
Maybe you’re in a rut.
The solution is as close as the nearest seed catalog.
"Two ways to liven up a boring garden are to try completely new crops and to try old favorites in unusual colors or shapes," suggests Mary McLellan, Extension Master Gardener program coordinator at Michigan State University.
Maybe you’ve never grown kohlrabi or salsify or Jerusalem artichokes. How about Indian corn? Or popcorn? Or, if you’ve grown popcorn before, what about the miniature ears with red kernels? Broom corn is another possibility.
In the squash family, decorative gourds, giant and miniature pumpkins, yardlong cucumber, luffa gourds and spaghetti squash may be what you need to break out of your rut of butternut squash, zucchini and slicing cucumbers.
In the salad portion of the garden, consider planting a mix of salad greens, often sold as mescluns, for a variety of leaf shapes, flavors, colors and textures for your salad bowl. Experiment with spinach and escarole, romaine and endive; and radishes in various sizes, shapes and colors.
There’s nothing wrong with globe-shaped red tomatoes and green peppers, but tomatoes and peppers come in a range of shapes, sizes and colors, from yellow cherry tomatoes and red cherry peppers to yellow banana peppers to orange pear-shaped and round white tomatoes. For the truly adventurous, there are hot peppers that range in heat from mildly spicy to four-alarm types (handle these with gloves -- really!).
Purple-podded snap beans, purple cauliflower, white pumpkins, chocolate-brown peppers, ivory-colored peppers that mature to lavender, and then red, pink or purple radishes, golden-yellow acorn squash and zucchini, yellow-fleshed watermelon, white-fruited eggplant -- the list of common vegetables in uncommon colors goes on and on, McLellan observes. Their eating quality is often just as good as that of standard varieties in more ordinary colors. When trying them for the first time, gardeners might want to plant them in addition to tried-and-true favorites rather than instead of them, she recommends.
"Then, if you decide that the new variety doesn’t measure up, you still have the old standby to fall back on," she explains. "But you’ll probably find that the variety of sizes, shapes and colors available in the seed catalog does indeed spice up the garden and make for a more interesting harvest."
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ANR Communications Contact: L. Johnson or M. McLellan
MICHIGAN STATE UNIVERSITY Telephone: 517-432-1555 or 353-3774
East Lansing, MI 48824-1039
EAST LANSING, Michigan -- When planning landscape changes and choosing ornamental plants, people tend to think of how the plants will look during the growing season.
Winter accounts for a substantial part of the year, however, so why not consider adding color and interest to the winter landscape as well?
Mary McLellan, Extension Master Gardener program coordinator at Michigan State University, suggests that evergreen foliage, persistent fruits, decorative bark and unusual growth habits can add visual interest to the landscape. Variations in plant shape and branching structure can also lend variety to the view.
Evergreen trees and shrubs are available in a wide variety of shapes, sizes and color variations. Their foliage provides a spot of color that contrasts with the snow. Snow on the branches gives the landscape a cozy, greeting card aspect.
Color is also available in persistent crabapple fruits and the twigs of red or yellow twig dogwood, she notes.
When they think of interesting bark, many people think of European white birch, with their stark white bark and black markings. Serious insect problems with European white birch make it a short-lived plant in the landscape, McLellan points out. London plane tree (a more disease-resistant relative of the native sycamore), river birch and other native birches, Chinese or lacebark elm, and paperbark maple offer textural or color interest without the pest problems of the exotic white birch.
An increasingly popular ornamental planted for its intriguing branch structure is Harry Lauder’s walking stick (Corylus avellana ‘Contorta’), a shrub with twisted, turned and corkscrewlike branches. Plant it where you can see its unusual silhouette from your favorite window and it can become a winter focal point in the landscape.
Crabapples, usually planted for their spring flowers, also offer a variety of shapes and growth habits, from almost columnar to short and broad with weeping branches.
As always when you’re choosing landscape plants, look past their ornamental traits and consider hardiness -- their ability to survive and thrive under local climatic conditions; adaptability to the soil, air and water drainage, and exposure to sunlight (or shade) in your proposed planting site; and the plant’s mature size and the space available for growth, McLellan advises. Choosing a plant adapted to local growing conditions, and planting it in a site that will give it room to reach its mature height and spread without getting involved with utility lines, septic systems or structures, will increase its chances of being an asset to the landscape for a long time.
Another consideration is its susceptibility to disease or insect pests, she adds. Major pest problems, like susceptibility to wind or ice storm damage, increase maintenance needs and detract from the other desirable traits that a plant has to offer.
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ANR Communications Contact: L. Johnson or M. McLellan
MICHIGAN STATE UNIVERSITY Telephone: 517-432-1555 or 353-3774
East Lansing, MI 48824-1039
EAST LANSING, Michigan -- Three gardeners are wandering through an array of perennial plants, each looking for a particular plant. Each finds what he or she is looking for and heads for the checkout line. Noticing that they’re all holding pots of the same plant, they begin to compare notes and find that each of them knows it by a different common name.
It’s not hard to see how confusion could result if the same plant were known by several names or several very different plants had the same common name.
"Because the plant names that people learn as they grow up can vary, common names are not very dependable," says Mary McLellan, Master Gardener program coordinator at Michigan State University. "Scientists and plant professionals -- and serious home gardeners -- use instead the binomial system developed by Linnaeus, the Swedish botanist, in the 18th century."
It is called a binomial system (meaning "having two names") because each plant has a name made up of two parts -- its genus and species. Red maple, for instance, is Acer rubrum. Black-eyed Susan or orange coneflower is Rudbeckia fulgida.
At the basis of the naming system is the botanical classification of plants into families of plants that share certain broad characteristics. Families are then broken down into groups of more closely related plants (in the same genus; plural is genera), which are distinguished from one another by their species names. For instance, maple have the generic name Acer, and members of the stone fruit family (cherries, peaches, plums, etc.) have the generic name Prunus.
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ANR Communications Contact: L. Johnson or M. McLellan
MICHIGAN STATE UNIVERSITY Telephone: 517-432-1555 or 353-3774
East Lansing, MI 48824-1039
EAST LANSING, Michigan -- Winter is tough on houseplants. True, they don’t have to deal with the weather outdoors, but they must struggle with low light levels, cool temperatures and overdry air indoors, and people who give them too much water.
Mary McLellan, Extension Master Gardener program coordinator at Michigan State University, says most winter houseplant problems are related to one or more of these factors.
"Overwatering is the main problem," she notes, "though it’s related to low light and cool temps in that, because of low light levels, plants aren’t growing as much in the winter as they did, so they don’t need as much water and probably no fertilizer. If people don’t adjust their watering and fertilizing practices, roots die and plants decline."
The first symptom of damaged roots is wilting of the top part of the plant. The plant looks as if it’s deprived of moisture when water is exactly what it has already had too much of.
What’s happening is that plant roots can’t function when the soil is saturated. Without oxygen in the soil, they can’t take up water, even though they’re surrounded by it. So the plant wilts. Adding more water doesn’t improve the situation.
Fertilizing may add to the problem by causing fertilizer salts to build up in the soil. They can interfere with water uptake or damage the roots. Again, the result is the same: the aboveground part of the plant wilts.
Dry air in the home plays a role in overwatering by drying the soil at the top of the container quickly. The lower portion, where the roots are, may still be quite wet, however. Rather than watering on a regular schedule or when the soil surface is dry, check the moisture one-third of the way down into the soil, McLellan advises.
"If the soil is dry at that level, it’s time to water," she sums up.
To keep houseplants healthy over the winter, either of two courses will work: either cut back on water and fertilizer and let plants go semi-dormant, or supplement natural light and provide somewhat warmer temperatures to keep plants actively growing. In other words, adjust the amount of water and fertilizer to the amount of growth that’s going on as a result of low light and cool temperatures, or make the environment more favorable to growth by increasing light and temperature levels, McLellan suggests.
Another tactic is to pot plants in clay rather than glass or plastic containers. Clay pots are porous, so some excess moisture can escape through the pot. Drainage holes and saucers to catch excess water should be emptied so the soil has every chance to dry between waterings.
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