Contact: Diane Relf, Extension Specialist, Environmental Horticulture
October 20, 1997
Winter damage to your plants can be minimized by planning. If you are preparing a new planting, select plants that are hardy in your part of Virginia. Consider plant materials that either are native or are known to be winter hardy in your area. Visit local arboreta, botanical gardens, or other public gardens.
Select Site That Offers Protection
If there are certain plants that you feel compelled to grow despite the fact they are of marginal hardiness in your area, select an appropriate site that offers some protection. For example, when planting broadleaf evergreens that are known to be easily injured, such as some varieties of rhododendron, azalea, camellia, daphne, and holly, select a location on the north, northeast, or eastern side of a building or other barrier where they will be protected from prevailing winds and intense winter sun. These locations will reduce the extreme changes in temperature caused by the direct sun warming the plant to higher than air temperature during the day. These locations will also delay spring growth, thus preventing injury to new growth of flowers from a late spring frost.
Avoid poorly drained soil or low spots that create frost pockets and sites that are likely to experience rapid fluctuations in temperature. Place plants away from house eaves and other snow or ice collecting areas where the snow or ice is likely to fall or slide onto the plants.
Follow Recommended Practices
Follow recommended cultural practices to keep plants healthy as a sure way to reduce winter injury to ornamentals. Plants that are diseased or deficient in nutrients are more susceptible to winter injury than strong, health ones.
Provide a fall fertilization after plants are dormant but before soil temperature drops below 45-50F. Avoid late summer or early fall fertilization while plants are still active as this stimulates late fall growth that is killed by the cold.
Proper pruning at an appropriate time throughout the year is also important in reducing damage by ice and snow. Remove any weak, narrow-angled, V-shaped crotches. Avoid late summer pruning that stimulates new, tender growth and reduces the supply of nutrients available to the plant through the winter.
Water Before Ground Freezes
Proper watering can be a critical factor. If autumn rains have been insufficient, give your plants a deep soaking that will supply water to the entire root system before the ground freezes. This practice is especially important for broad and needled evergreens. Watering during January, February, and March when there are warm days is also important.
Mulching is an important cultural technique throughout the year. It reduces weeds, helps control erosion, and reduces water loss. This last factor is of importance in preventing winter damage. A 2- to 4-inch layer of a mulch material, such as pinebark, fir bark, or pine needles, will reduce water loss and help to maintain uniform soil moisture around the roots. It also will help reduce the alternate freezing and thawing of the soil which causes some shallow-rooted plants to heave out of the soil.
More gardening information is available in the Virginia Gardener Newsletter.
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