Yard & Garden Line News Volume 1 Number 11                                                               September 15, 1999

Features this issue: Fall Gardening Tips Harvesting Culinary Herbs Ripening Tomatoes Indoors Fall Watering Over-Wintering Tender Bulbs and Plants September Is Head Lice Prevention Month Fall Is Clean Up Time! Powdery Mildew Planning for Next Year's Raspberry Crop Winter Injury to Plants in the Landscape Editorial Notes

Fall Gardening Tips
Deborah Brown, Extension Horticulturist

Bulb planting. Image credit: Netherland Flower Bulb Information

Here are some fall garden and landscape tips for Minnesota:

• Fall clean-up and yard work can provide enjoyable outdoor exercise on brisk, sunny days. On average, this work burns 300 calories an hour, so you can feel virtuous while doing your chores!
  
  
• Have some large cardboard boxes on hand to cover tender garden plants those first nights of frost. Often when you protect them from early frost, they can go on to bloom and grow for another week or two.
  
  
• Tomatoes need average daily temperatures of 65 degrees or more to ripen well. When daytime temps are consistently below this, pick the fruits that have begun to change color and ripen them indoors, out of direct sunlight.
  
  
• Late September through early October is the time to plant spring flowering bulbs for a beautiful burst of color early next season. If you're not sure which end of a bulb is the top, plant it on its side. New growth will orient itself to gravity; the stem will always grow upright and the roots, downwards. This is called "geotropism".
  
  
• When you plant bulbs, be sure to dig holes deep enough to accommodate the bulb and three to five inches of soil on top of it (depending on the type of bulb). Never mash the bulb into the soil. You may damage its basal plate (the bulb's bottom, from which its roots will emerge), causing it to rot.
  
  
• Studies have shown that bone meal alone is not enough to ensure good tulip growth, particularly if you want the bulbs to produce for several years. Instead, incorporate "bulb food" or a balanced fertilizer such as 10-10-10 in the soil below the bulbs. Fertilize again when plants emerge next spring.
  
  
• Before putting away wooden handled tools for the winter, clean them and sand the wood smooth. Then apply a coat of brightly colored water-resistant paint to keep the wood from drying and splitting. It also helps you spot the tools if you forget them in the garden.
  
  
• When all your outdoor chores are done, reward yourself with a copy of the new Minnesota Gardening calendar for the year 2000. Find a comfortable easy chair and catch up on the great gardening magazines you've been too busy to read this summer.

Harvesting Culinary Herbs
Deborah Brown, Extension Horticulturist

'Siam Queen'basil. Photo credit: Johnny's Selected Seeds

Pick herbs while their leaves are still green and healthy looking. Rinse them in cool water, then pat them dry gently with a soft rag or paper toweling. Hang them upside down in small bunches to dry. (You can usually suspend several bunches from one metal clothes hanger.) The room should be warm, well-ventilated, and preferably dark.

Once they're dry, in a week or so, put them in air-tight glass jars. Don't crumble herb leaves or strip them of the stems until just before you're ready to cook with them; much of their aromatic essence will be lost in the process if you crush them prior to storage.

Making herbal vinegar is an easy project when you harvest herbs. Force a small bunch of fresh herbs down the neck of a clean wine bottle (you can buy bottles and corks where they sell wine-making supplies and, sometimes, at craft shops). Fill the bottle with white wine vinegar, push the cork in, then if you wish, seal the cork by dipping the neck of the bottle into melted wax.

(For colorful wax, melt candles in the top of a double boiler, over water. Never melt wax directly in a pan over a burner.... unless you'd like a good excuse to remodel your kitchen!)

The vinegar will be ready to use within the week, but it will stay good for years. In fact, you can refill the bottle two or three times with more vinegar and the herbs will still flavor it nicely.

Ripening Tomatoes Indoors
Deborah Brown, Extension Horticulturist

Tomatoes. Photo credit: Deb Brown

Tomatoes taste best when allowed to ripen on the vine, but this year's unusual weather has left gardeners with lots of tomatoes that have been slow to mature.

When temperatures are expected to drop only a little below freezing, you may choose to cover the plants with old sheets or blankets to trap warmer air around them over night. Then uncover them as temperatures warm during the day. But this effort only makes sense if you expect weather conditions to improve enough so ripening may still occur.

Your other option is to pick the tomatoes. Any that have already turned light green (on their way to pink, and finally red) can be expected to ripen satisfactorily indoors. Of course, they'll never taste as wonderful as vine-ripened, but they won't be bad.

Any that are still dark green when frost threatens can be made into picalilli or green tomato relish.... or you can invite a bunch of girlfriends over, rent a video of Fried Green Tomatoes, and have a theme party.

Indoors, tomatoes ripen best when kept out of direct sunlight, at temperatures that range from 60 to 70 degrees. You can keep them in the basement, but if it drops below 55 degrees, flavor will suffer. Wrap fruit individually in tissue paper; then if one begins to decay, it won't take its neighbors with it.

Another way to ripen tomatoes is to pull entire plants out by the roots, then hang them up indoors out of direct sunlight under moderate temperatures. Check them every few days and remove any fruit that looks ripe. Be sure to cull out any that have soft spots or are rotting, so as not to attract fruit flies.

When you plan your garden next year, remember to include some early-ripening tomato varieties along with your mid and late-season favorites.

Fall Watering
Deborah Brown, Extension Horticulturist

Watering the lawn. Photo credit: U of M Extension Service

Though we usually have ample rainfall in autumn, it's not uncommon to have to supplement what Mother Nature delivers. For instance, it's important to water newly planted tulips and other spring-flowering bulbs so they make roots before the soil freezes. If weather remains dry, water your bulb beds once a week.

Don't forget your flower or vegetable garden, either, especially if you've planted some cool season vegetables such as broccoli, spinach or radishes for fall harvest. Produce will be larger and tastier if adequate moisture supplies are maintained.

If it's dry, it's also a good idea to water newly planted trees and shrubs every ten to fourteen days. Be careful, though, not to overwater if you have heavy, clay soil. Continue watering periodically, IF NECESSARY, until the soil freezes. In fact, you should mulch those plants with several inches of woodchips or shredded bark to prevent early freezing. (Roots continue to grow as long as soil temperatures don't drop below forty degrees F.)

Evergreens will come through winter in better shape if they're not moisture stressed. We used to think that just meant watering regularly in autumn, but it also involves watering in July and August whenever weather is hot and dry. Even though there's been plenty of rain this summer, it's a good idea to water these plants if we run into a dry spell in fall.

Remember, the cooler it gets, the longer plants can go between waterings. Every year some people lose newly transplanted trees and shrubs because they water them daily, thinking they are being helpful, when really they're just rotting the roots, especially in clay soils.

Over-Wintering Tender Bulbs and Plants
Deborah Brown, Extension Horticulturist

Holiday cactus. Photo credit: Robert Mullin

Never wait until frost threatens to bring tender plants indoors for the winter. Most houseplants, whether flowering or grown primarily for their foliage, originated in warm, tropical or sub-tropical climates. They can gradually become accustomed to cooler fall temperatures, but the transition indoors will be easier if there isn't a huge difference between growing conditions indoors and those they're experiencing outdoors.

Two notable exceptions are azaleas and holiday cacti. They will actually begin to set flower buds in response to falling night temperatures. Keep them outdoors until nights drop into the mid or upper 30's, then place them in a cool, sunny location indoors. An unheated spare bedroom or basement window often works well until buds are quite visible. Then you can bring them into living areas to be enjoyed as the blossoms open.

If you plan to allow amaryllis bulbs to "go dormant" in the basement before forcing them to bloom again this winter, they may be left outdoors as long as temperatures remain above freezing. But if weather is cloudy or consistently cool and wet, there's no advantage to leaving them outdoors as long as possible.

If you prefer to keep your amaryllis plants growing actively throughout the year, and blooming "naturally" some time next March, bring them in before outdoor temperatures drop signifcantly below those indoors. (To keep them active year-round, place amaryllis by your brightest, sunniest windows, pulling them back a bit only when they're blooming.)

Several of our favorite summer-flowering garden bulbs also lack winter hardiness and must be brought indoors for winter storage each autumn. However, you may leave most of them outdoors until frost damages their foliage. Canna and calla lilies, gladiolus, dahlias and tuberoses are among the more common bulbs in that category. But tuberous begonias, montbretias and caladiums should not be allowed to experience such cold temperatures, and must be taken in before frost threatens.

September Is Head Lice Prevention Month
Jeffrey D. Hahn, Assistant Extension Entomologist

Adult louse. Photo credit: National Pediculosis Association

With school in session again, expect problems with head lice to increase. Most head lice are found on young children, clinging to hair shafts near the scalp. Adult head lice are about 1/8 inch long, grayish, flattened, and wingless. Their legs are claw-like, designed for holding onto hair. Lice eggs, commonly referred to as nits, are very small (1/30 inch long). They are attached to hair within 1/2 inch of the scalp.

Head lice do not jump or fly. But they can move from an infested individual to another person when children are playing or otherwise involved in an activity that allows close contact. Head lice can also move to new hosts when an infested child shares combs, brushes, scarves, clothing, hats, towels or similar items

Fortunately, head lice do not transmit disease, although their presence can be very embarrassing. Lice inject a saliva into their hosts as they feed. This results in itching which at best is annoying and at worst can result in infection if scratched too vigorously.

If lice are reported from your school, check your children regularly for. Start from the back of the neck and move forward, parting their hair so you can examine the base of the hair shaft. Use a good light and a magnifying glass if possible. Objects found loose are probably not anything important; lice or nits are tightly attached to hair. Also educate your children about how lice infest people. Children can help prevent infestations by not sharing combs, brushes, clothes, scarves, and similar articles with friends.

Nit. Photo credit: National Pediculosis Association

The first step in the proper treatment of head lice is correct diagnosis of the problem. If you find something suspicious, have it diagnosed by a health care professional or entomologist. Not all suspected cases actually involve lice. If you have a diagnosed case of lice in your family, there are several tactics to consider.

In the past, insecticidal products have been the first step in the war on head lice. However, there are an increasing number of reports of resistance by head lice to these products, causing concern in their use. Insecticides containing permethrin and pyrethrins are common in shampoos and lotions that can be purchased over-the-counter. If you use one of these products, follow their directions precisely! Remember, they contain insecticides and should be used with great care and respect. Lindane is available by prescription. However, this is the most toxic of all the products and should be used only as an absolute last resort.

If a family is still infested after using an insecticidal product, discontinue using it. Applying a shampoo or lotion repeatedly not only does not improve effectiveness but put the child or adult at greater risk because of increased exposure to insecticides. Don't use dubious methods, such as kerosene, pet shampoos, or other insecticides. These methods are not more effective, just more dangerous.

Regardless of how effective insecticidal products are, physical removal is essential in head lice control. Use nit combs to remove the lice and eggs. You can purchase nit combs through pharmacies or from the National Pediculosis Association (see web site below). All bedding and clothing of infested people should be washed or dried at a high temperature. Pillows or other nonwashable items should be placed in plastic bags and placed in a cold place for several days. Check other people in the family, even if they don't appear to be infested.

Head lice maintain an intimate relationship with their host and can not survive off a human for more than two days. Because of this, thoroughly cleaning a home is not important. Concentrate on treating the individual. Never apply insecticides inside a home to control head lice.

For more information, access the National Pediculosis Association's (NPA) website at http://www.headlice.org

Get the low down on this month's insect pests at Insects http://www.extension.umn.edu/projects/yardandgarden/Ent.htm

Fall is Clean Up Time!
Chad Behrendt, Extension Plant Pathologist

Oak anthracnose on leaves. Photo credit: Chad Behrendt

Apple scab on leaves. Photo credit: Plant Disease Clinic

Dutch elm disease flag. Photo credit: Robert Blanchett

Fireblight's "shepherd's crook".

Black knot. Photo credits: Plant Disease Clinic

As we approach the end of the growing season and prepare for winter, we need to reflect on the severity of disease this year and remember that most fungi survive winter within infected plant debris. Fungal material such as mycelium, spores, or specialized reproductive structures may persist in the soil, in fallen leaves, or in dead branches remaining on the plant. In the spring, these structures produce spores that cause new infections. However, before infection can occur, three components must be present: a susceptible host, a virulent pathogen, and a conducive environment. If one of these components is missing, no disease will occur. Therefore, as a management strategy, we can try to minimize the amount of fungal material that survives winter.

One way to minimize winter survival is to follow a thorough sanitation program. All infected plant debris both on the ground, as well as within the tree should be removed and destroyed in the fall. This includes dead or infected leaves, branches, and fruit. Collected material should be buried, burned, or discarded. Collected material placed in the compost pile will not decompose before spring.

Although it is impossible to remove all of the infected material, sanitation does help reduce the overall amount of viable fungal material, and in turn the severity of disease. Sanitation is a recommended practice and can be beneficial, but may not always be effective; many fungi are able to disperse long distances to neighboring plants when splashed by water and blown by wind.

Three common leaf-spotting diseases that may be minimized with sanitation practices include ash anthracnose, oak anthracnose, and apple scab. All of these fungi, ubiquitous in nature, occur on an annual basis. As a result, sanitation should reduce the severity of disease and overall stress on the tree, but will not prevent infection.

Two other diseases well managed by sanitation practices include Dutch elm disease and oak wilt. Removal of infected trees prevents the dispersal of spores, by insect vectors, from infected trees to healthy trees, stopping the overland spread of these two diseases. Infected trees in the red oak group need to be removed before April the year following infection, while elm trees need to be removed as soon as possible. Smaller branches from infected trees should be chipped, while larger material may be debarked, burned, or stored as firewood under heavy plastic.

Fall is also a good time to mark dead or infected branches in need of dormant season pruning. This practice, similar to sanitation, removes fungal material that is surviving in infected shoots and branches on the tree. This material, if not removed, will produce spores capable of causing new infections next spring. All branches containing cankers, knots, galls, or dead shoots should be marked for pruning. The best time to mark branches is in late fall after leaf drop, so infections are more visible. Marked branches should be pruned during late dormancy, usually late February to early March. It is important to remove all infected material before fungi become active in the spring. Pruned branches should be burned, buried, or chipped.

A number of fungal and bacterial diseases including cedar apple rust, fireblight, black knot, and a variety of other cankers and galls can be minimized through therapeutic pruning. To prevent the dispersal of fungal material from infected branches to healthy branches, pruning tools should be sterilized between cuts with a 10% bleach solution or 70% alcohol. Although sterilization is not a necessary practice for all diseases, it is extremely important when removing bacterial infections such as fireblight.

In addition to therapeutic pruning, trees requiring dormant season fungicide application should be identified and marked in the fall. Fungicides such as lime-sulfur or Bordeaux mixture can be applied to severely infected trees during late dormancy, before buds begin to swell in the spring. A few of the common diseases controlled with the use of dormant season sprays include black spot on rose, black knot of cherry, and plum pockets.

Finally, it is important to maintain plant vigor throughout the entire growing season, so plants enter dormancy in a healthy state. Stressed plants are more likely than healthy plants to suffer winter injury. To maintain plant vigor, properly fertilize and mulch plants during the growing season and water trees during dry periods to reduce drought stress in late fall. Other cultural practices include wrapping thin barked trees such as maple, to prevent sunscald.

Powdery Mildew
Chad Behrendt, Extension Plant Pathologist

Powdery mildew on lilac. Photo credit: Plant Disease Clinic

Powdery mildew, a common fungal leaf disease, is probably beginning to appear in the home landscape on lilac and other ornamental plants such as rose, phlox, begonia, zinnia, and alpine currant. This disease, unlike most, does not usually kill the plant it is living on, but does derive nutrients and water from the plant causing a reduction in growth and reproduction.

Powdery mildew typically appears on the surface of infected leaves as spots or patches of white to gray powdery, mildew-like growth. Although powdery mildew is quite common, it requires certain environmental conditions before infection can occur. Both temperature and relative humidity are important factors with cool temperatures and high humidity resulting in maximum disease severity. These conditions tend to occur when plants are grown in close proximity, damp shaded locations, or in areas with poor air circulation. Powdery mildew also tends to be most severe when cool nighttime temperatures follow warm daytime temperatures.

Control or management strategies should begin with improved cultural practices such as increasing light penetration, increasing airflow, or thinning crowded plants. Chemical control measures are not usually required in the home landscape, but sulfur can effectively control powdery mildew. Make sure to read the label, since sulfur can be phytotoxic to certain plants.

Test your diagnostic savvy monthly with Disease Watch at: http://www.extension.umn.edu/projects/yardandgarden/Plpa.htm
Planning for Next Year's Raspberry Crop
Chad Behrendt, Extension Plant Pathologist

Anthracnose. Photo credit: Chad Behrendt

Growing healthy, abundant raspberries takes a lot of time, effort, and dedication. From early spring to the time of harvest, you are continuously watching, nurturing, and caring for your plants. DO NOT STOP NOW!

Fall is a very important time to prepare for next year's crop. Thorough fall clean up and sanitation practices can greatly reduce the number and severity of plant diseases, as well as prevent future problems. It is important to remove and destroy all infected canes from your raspberry patch this fall.

Fall is a good time to thoroughly scout your raspberry plants for cane diseases. A number of different cane diseases occur on raspberries, but two of the most important include raspberry anthracnose and spur blight. Both of these diseases can cause defoliation, wilting of shoots, and cane death, resulting in severe yield loss next year.

Spur blight. Photo credit: Chad Behrendt

Although both of these diseases become active early in the season and infect plants during the growing season, they are often observed during harvest or fall renovation when canes are leafless and more exposed.

Raspberry anthracnose is easily identified by the small oval lesions occurring on the cane. In late spring, these lesions appear as red to purple circular lesions on the primocanes. The center of these lesions later turns pale brown to ash gray, while the margins become raised and purple. Anthracnose also infects the leaves, with small, purple to brown spots developing on infected leaves.

Spur blight is most frequently observed as a large elongated lesion surrounding the nodes of primocanes. These lesions appear purple under the heavy primocane wax, but turn brown when the wax is rubbed off. In winter, lesions turn silver to gray and become difficult to identify. Initial infections begin along leaf margins and progress inward, through the petiole, to the stem. Infected leaves develop a brown ‘V’ shaped lesion with yellow margins, and eventually fall from the plant. Floricane leaves are susceptible, but rarely infected.

To manage these two diseases properly, identify, remove, and destroy all infected canes. For additional control a dormant season lime-sulfur fungicide spray can be applied. The best time of application is late winter to early spring, just prior to bud break.

Winter Injury to Plants in the Landscape
Patrick Weicherding, Extension Educator, Horticulture

Frosted trees. Photo credit: Beth Jarvis

Minnesota gardeners are keenly aware of seasonal effects of temperature, particularly freezing temperatures, on the growth of landscape plants. Woody plants are able to survive freezing temperatures because of metabolic changes that occur in the plant between summer and winter. Terms such as "cold hardy", "frost hardy" and "winter hardy" are used to describe woody plants that can survive freezing temperatures without injury during winter dormancy.

Cold hardiness is determined by the genetic capacity of a plant to acclimate (transformation from a non-hardy to hardy condition) to freezing temperatures. This capacity can be influenced by plant care practices. While the cold hardiness of a species is usually considered to be the lowest midwinter temperature plant tissues can endure, injury frequently occurs during autumn or spring when the plant is not at its maximum hardiness. Thus, injury can occur during the autumn, winter, or spring seasons depending on the extent of acclimation or deacclimation (process of transforming from hardy to non-hardy condition). Winter injury may be manifested as excessive browning of evergreen foliage, injury or death of flower buds, splitting of bark and wood tissues, or death of roots. The extent of injury is often difficult to determine, and may only be exhibited as delayed bud development or slightly reduced growth.

Low temperature injury, often called freeze damage, can be caused by intra- or extra-cellular ice formation within the plant. When intra-cellular ice is formed, crystals originate within the protoplasm of plant cells. This type of ice formation occurs infrequently and only when the temperature decreases very rapidly. If the ice formation is extensive or ice remains for a long period of time, cells rupture and die.

The second type of freeze damage occurs when extra-cellular ice forms during normal winter conditions. When freezing conditions exist, water moves out of plant cells in response to the low temperature and back into cells when temperatures rise above freezing. This type of freeze damage is not lethal to most woody plant species that have been properly acclimated. Injury can occur, however, if the cells are dehydrated for relatively long periods of time, or subjected to very low temperatures.

Yew. Photo credit: Beth Jarvis

Desiccation injury occurs when water is lost from evergreen plants to the atmosphere faster than it can be replaced through absorption of water by roots.

Desiccation injury is a function of the degree and length of time that stress is imposed. When leaf and air temperatures are low and the relative humidity high, little moisture loss occurs. However, when leaf and air temperatures are high and relative humidity is low (as often occurs in winter), moisture loss can be excessive and injury extensive. Further injury can occur if water cannot move within the plant to replenish desiccated leaf and stem tissues or when roots from cold or frozen soil absorb insufficient water. Wind movement across plants may increase the rate of moisture loss.

Most woody landscape plants acclimate or develop hardiness to freezing temperature in response to changes in light duration and temperature. Acclimation is a two-stage process. The first stage is initiated by decreasing day length and results in partial hardiness. The second stage is initiated by subfreezing temperatures and results in full hardiness and acclimation.

For many species, the shortened photoperiod (hours of daylight or light duration) of late summer initiates the hardening process by slowing vegetative growth. The time it takes for a plant to stop growing differs widely. Some plants stop growing in July or August and others continue to grow into autumn. These differences are due to hormonal balances in the plants controlled by day length and modified by temperature.

Leaves are the receptors of the short-day signal. After growth stops, the short-day photoperiod triggers a hardening signal that is transferred from the leaves to the stem and branches. The short-day signal results in partial cold hardiness. The timing and rate of hardening can be altered by temperature, while day length is predictable by calendar dates. The hardening response in a single plant may vary from year to year because of temperature differences.

Cool temperature initiates the accumulation of sugars, modification of proteins and changes in cell membrane permeability that are associated with increase in cold hardiness. While most plants require short photoperiods and lower temperatures to develop full hardiness, some harden only in response to low temperature regardless of photoperiod.

Freezing alone contributes to hardiness. Once leaves and stems of evergreens harden enough to withstand freezing, being frozen makes them hardier. The freezing response is strictly localized and is not translocated. In other words, if lower leaves are acclimated to freezing that does not necessarily mean the upper leaves are also hardened.

Iced junipers. Photo credit: Beth Jarvis

Although autumn temperature above 60 degrees F reduces root hardiness, it appears that cool temperature contributes to slowing or stopping root growth. Roots cannot acclimate to the same extent as shoots, so it is fortunate they are protected by a large volume of soil, which serves as insulation.

Finally, the water content of woody tissues decreases as acclimation to winter conditions proceeds. Most research, however, supports the practice of irrigation late in the growing season to assure the normal rate of cold acclimation. This practice is especially beneficial for plants, such as rhododendrons, which continue growth late into the season and are susceptible to early freeze damage. Since woody plants appear to have a built-in mechanism to reduce water levels when they acclimate, reducing soil water may not benefit the development of maximum midwinter cold hardiness.

So, what does all this mean for winter hardy Minnesotans who want to protect their woody plants from the ravages of Minnesota winters? Gardeners can assist, to some degree, in plant acclimation to winter conditions. The amount of nitrogen fertilizer applied should be reduced after mid-July and stopped by late summer. Commercial growers decrease the rate of nitrogen fertilizer by approximately one-half and double the rate of potassium application in late summer. In other words, stay away from lawn fertilizers that are high in nitrogen and low in potassium and often sold as "winterizers" for your home lawn. Woody plants should enter the autumn as healthy as possible, but not rapidly growing, or acclimation may be affected.

Tissue desiccation during winter, especially with evergreens, is one of the most common forms of winter injury. The soil in which evergreens are being grown should be well irrigated in mid-to-late autumn, before the soil freezes. If the landscape where evergreens are located is in a dry site, sandy soil, or under the overhang of a roof, the soil should be irrigated in midwinter when the temperature is above freezing.

Extra precautions that Minnesota gardeners can take to protect woody plants in the landscape include mulching, tying and wrapping.

Apply a layer of mulch, 3 to 4 inches deep, after the soil freezes to keep the soil cold rather than protect the soil from becoming cold. This practice will reduce injury from plant roots heaving (coming out of the soil) because of alternate freezing and thawing. Mulch maintains a more even soil temperature and retains valuable soil moisture.

Apply bark products, composts, peat moss, pine needles, straw, hay or any one of a number or readily available materials from the local garden center. Pine boughs or remains from Christmas trees can be propped against and over evergreens to help protect against damage by wind and sun.

Binding to prevent damage. Image: U of M Extension Service

Multiple-leader (branched) plantings such as arborvitae, juniper and yew may be damaged by the weight of snow or ice. Prevent branch breakage by fastening heavy twine at the base of the plant and winding it spirally around and upward to the top and back down in a reverse spiral. This technique is needed more as plants become larger and begin to open at the top.

A wrap of burlap or canvas can offer protection to plants against desiccation from sun and wind and drift from de-icing salts applied to driveways and streets. Wrap the "body" of the evergreens, but do not cover the top of the plant, as some light is necessary during the winter.

Wrapping trunks of smooth barked trees, for many years a standard practice, has recently been debunked. Tree wraps have not been found effective and indeed may cause more injury when left on too long. Loose fitting guards or boards tied to the south and southwest side of the tree trunk that permit air circulation and shade the bark have been found effective.

Applying an anti-transpirant, also called anti-desiccant, is generally not effective winter protection.

Editorial Notes

'Stargazer' lilies.

Wall of coleus. Photos: Beth Jarvis

While doing a little "stargazing" of my own, it looks like upcoming issues will include a veterinarian's advise on how to reduce "dog spots" in your yard, is it worthwhile to know your apple's rootstock?, mycorhhizae, and what's new in the blueberry patch?

I'm still collecting suggestions for articles for the near future or even for next year. Drop me a note if you have ideas.

We publish the Yard & Garden Line News twice a month during the gardening season, on the first and 15th of the month. November through March, we publish monthly, on the first.

Please feel free to cut and paste any of the articles for use in your own newsletters. All we ask is that you give our authors credit.

For plant and insect questions, visit http://www.extension.umn.edu/askmg. Thousands of questions have been answered, so try the search option in the black bar at the top left of the board for the fastest answer.

If you would like to receive an e-mail reminder when the next issue of the Yard & Garden Line News is posted to the web, just send an e-mail to: listserv@lists.umn.edu (note: the second E in listserve is omitted), leave the subject line blank, then in the body of the message, type: sub yglnewslist or to unsubscribe, enter: unsub yglnewslist

Happy gardening!

Beth Jarvis
Yard & Garden Line Project Coordinator

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