Rick Durham, Consumer Horticulture Extension Specialist, University of Kentucky
 

Those pansies need winter protection.

You may have noticed that the foliage on the pansies you planted last fall has turned a dull green color and the leaves have started to wilt. Fear not, this is a normal response to cold weather. However, this means that it is probably time to take some protective measures to ensure that your pansies make it through the winter. The biggest problem faced by pansies is frozen soil coupled with drying winds. This will rapidly dessicate the plants and chances are they may not recover. If there is snow cover, the plants will be well protected from the harsh winter weather. In the absence of snow cover, a light mulch of straw about 2 inches think, will protect the plants from drying out on cold windy days without snow. The straw cover should start and continue as long as temperatures are consistently below 20F. Pull back the straw when the weather warms else the plants may suffocate as they resume growth in the spring.
 

Protecting trees from sun scald.

Sun scald is a conditions that affects the trunks of trees. It is characterized by elongated areas of dead bark on the south or southwest side of the trunk. Sun scald is a type of winter injury that occurs on very cold but clear days. As the sun's rays strike the surface of the trunk, the trunk's surface and underlying tissue can warm substantially, even to the point that the cambium tissue under the bark will become active. The damage occurs when the sun's rays are blocked abruptly by something such as a building, hill, or cloud cover. This will promote rapid cooling and freezing of the trunk surface tissue and result in injury to the underlying cambium. Young trees, newly planted trees, and trees with thin bark are especially susceptible to sun scald as are trees that have had their lower limbs removed so that the trunk is now more exposed to the sun. Also, trees that have recently been transplanted from a shady area to a more sunny location tend to be very susceptible. Older trees are generally less susceptible since their thicker, and sometimes furrowed bark will offer some insulation from the warming of the sun.

If you have trees susceptible to sun scald, here are some options for their protection. Trunk wraps are the most common form of protection. They are light in color and so reflect much of the sun's radiant heat and keep the trunk a more constant temperature. Wraps should be applied in fall and removed in spring after the danger of frost is over. Wrap young, newly planted trees for at least two winters or until thicker bark has formed. Thin-barked trees should be wrapped for at least 5 winters. If you have many trees to protect, say in a fruit orchard, it may be easier to apply a coat of light-colored latex paint to the trunk. Dilute the paint with an equal volume of water before applying. Some people even shade the trunk temporarily on cold days by leaning a board against the south exposure during cold weather. If sun scald does develop, remove the dead tissue in spring by cutting into the bark until live tissue is encountered. Cut a smooth outline around the damaged area and leave the wound open to heal. Sprays advertised to aid in healing wounds rarely do and should not be applied to the cut surface. It is also unnecessary to wrap the area. Simply leave it open to heal. Only treat the area if disease or insect damage becomes apparent. Your county extension agent can assist in making a proper diagnosis if this occurs.
 

Winter injury, is it permanent or not?

Plants may exhibit many symptoms of injury after a severe winter. Among these symptoms may be broken limbs, discolored foliage and twigs, and heaved roots and stems. During winter one should only remove broken or obviously dead limbs. The best diagnosis of winter injury is assessed in spring once regrowth has begun. At that time, dead branches can be pruned back to within one inch of a live bud or back to the branch color where one branch intersects another. Do not remove branches that show green just below the bark since these are still alive and may yet begin growth. Any branches that have not shown regrowth by late spring should be removed since dead tissue can provide an entry point for disease and insects. Discolored needles on evergreens may regain their color, or stems may produce new needles if damage is not severe. Broad-leafed evergreens that exhibit leaf damage will usually produce a new flush of leaves. If this does not occur, prune away damaged or broken tissue to stimulate new growth and reshape the plant. Finally, if a plant's root system has been partially heaved due to alternate freezing and thawing of the soil, replant these plants as soon as the soil thaws. Herbaceous perennial plants that were not adequately mulched in fall are most likely to exhibit this problem. Small plants may be pushed back into the ground with little effort, while larger plants may require lifting the root ball and replanting it at the depth is was previously growing. A light application of fertilizer in spring will help to stimulate new growth and compensate for any damage that may have occurred to the plant.
 

Forcing branches of woody plants into flower.

Winter can be quite bleak at times. A splash of colorful flowers would do wonders to revive the garden enthusiast among us and give us hope that spring is just around the corner. Why not consider forcing some branches from spring-flowering trees and shrubs. Select healthy branches with numerous flower buds present. The flower buds are usually plumper or longer than the vegetative buds. If you are forcing fruit tree branches, choose those that have abundant spurs (short lateral branches that bear most of the flowers and fruit). Remember to follow good pruning practices when you remove branches from a tree or shrub. After bringing the branches indoors, make a second, slanted cut at the base of the branch. If the temperature was below freezing when the branches were cut, immerse the entire branch in cool water for several hours or overnight. For forcing, place the branches into slightly warm water containing a floral preservative, up to about 3 inches from the base of the branch. Allow the branches to set for about 30 minutes and fill the container with additional water containing the preservative. (Hint, make your own preservative with 2 cups lemon-lime soda, 2 cups water, and ½ teaspoon chlorine bleach.) Keep the branches in a cool (60-65F) area, away from direct light, and keep the water level at its original height. Once flower color is evident, move the branches to a well-lit room but away from direct sunlight. The branches can then be removed from the forcing container and arranged to suit the occasion. Remember to keep plenty of water in the container and keep the branches in a cool location to prolong the life of the arrangement.