CARING FOR YOUR LANDSCAPE AFTER A LONG, COLD WINTER SEASON
MIDLAND PARK, N.J. -(April 9, 2015)If you are a winter person then you’ve had plenty of opportunities to sled, ski and build snowmen, but even winter-lovers are tired of the cold temperatures and snow after all the heating bills, school closings, icy driveways and roads.
Plants in New Jersey are no different; they feel the effects of a long winter, too. Cold weather can cause all types of problems for your lawn and plants. For example, heavy snowfalls may break limbs and rapid temperature changes can damage plant tissue. But that doesn’t mean you can’t still have a beautiful landscape this spring.
Using my knowledge of frequently asked questions this time of year, I compiled this list to help homeowners restore their landscape in the aftermath of cold-weather.
Remove broken branches on trees and shrubs. Branches that were broken or damaged by heavy snow load, ice or wind need to be properly trimmed. Frayed limbs are like open wounds to your trees and shrubs. Diseases and insects are more likely to cause damage if not properly pruned.
Winter burn on evergreens. In late winter or early spring, you may see brown or scorched tips on your evergreens. During the winter, bright sunlight and strong winds dry out needles and broad-leaf foliage. Because the stems and roots of evergreens are frozen, water is unavailable to replenish the loss of moisture. Rapid drops in temperature after a warm sunny day can also cause further injury to the plant. This spring, as your evergreens break their dormancy, lightly prune branch tips to improve their appearance and encourage new growth. In future years, applying an anti-desiccant in late fall and early winter, can also help to reduce transpiration and minimize damage to the foliage.
Bark splitting. This occurs when warm day temperatures are followed by extreme drops in temperatures in the late afternoon evenings. Both young and old trees with smooth bark are the most susceptible when the sun warms the trunk in the winter.
Deer, rabbit damage & rodent. Check your shrubs and evergreens for the tell-tale sign of winter browsing by deer, rabbits & rodents – that is 45 degree angle cuts near the base of a plant. Sometimes corrective pruning can re-establish a plant’s attractive habit, but it may take a couple of years of attentive pruning to fully recover. Once plants begin to grow in spring, also look for signs of deer and rabbits nibbling on the emerging buds and shoots of your shrubs and perennials. After a cold winter with lots of snow coverage, these critters will be hungry. Protect any plants immediately that show signs of damage by installing a wire cage if possible or spraying repellent. In extreme cases, the damage may be too great and the plant will need to be replaced.
Plant winter hardiness. Horticulturists rely on hardiness ratings to determine the potential survivability of each plant species in particular regions of the state. The ratings are based on field trials of the species in USDA-defined hardiness zones. Hardiness zones are determined by average low temperatures for a given region of the country, and not by extreme low temperatures. To ensure the long life of your landscape I recommend using native plants within New Jersey’s hardiness zone. Those species that are marginally hardy to a particular zone are especially vulnerable to cold injury.
Assessing winter injury. Because of limited root growth, it is not unusual to see newly-planted specimens die after a brutal winter. In the worst years long established plants can die, including some native species. In most cases it is species, which are marginally hardy that experience the most losses. Usually winter damage does not become apparent until spring when growth normally resumes. Typically, winter damaged plants exhibit the following symptoms: Slow to initiate growth or show distorted growth, death of leaf and flower buds, or dieback of shoots and branches.
Plants that do not bud in spring. Monitor plants as temperatures rise and your landscape begin to show signs of new growth. Cold injury will vary by plant – species, age and general health – as well as site location and soil conditions. Snow cover is also an important factor. It provides protective insulation as it mounds up around the base of our shrubs and covers our perennials as well as protecting tree and shrub roots that are close to the surface. Snow cover also protects against the desiccating effects of winter winds. Often, in the spring, you will see winter burn only on the portion of the plant that was not buried under snow! The Forsythia plant buds for example are prone to winter kill when temperatures dip to -10°F. After a very cold winter, blooms may appear on the lower part of the plant (the part protected by snow cover), while the upper branches will only have leaves due to the flower buds being winter killed.
Reduction in pests/diseases. One upside to the cold winter temperatures are the reduced number of pests and soil-borne diseases. Those species that have been multiplying or spreading unabated during the mild winters of recent years, may be knocked back significantly.
Poor looking lawn. Early this spring, you may discover that your lawn has a grey, moldy look to it. Snow mold shows up after winters of heavy extended snow cover and is aggravated by excessive use of fast-release nitrogen fertilizers in the fall. It typically occurs in areas where snow drifted heavily throughout the winter or where snow was piled when shoveling.
Care for damaged plants. Before pruning out what appears to be a dead plant, wait! Caution as dead looking plants may still be alive. The extent of winter damage can best be determined after new growth starts in the spring. We recommend waiting until Memorial Day as the time for final determinations of overall health. It’s best to check for living tissue by taking a small pocket knife or hand pruners, and gently cut into the wood to see if the tissue is green or brown. Damaged plants take their time before new growth emerges. Broadleaved evergreens showing leaf damage will usually produce new leaves if branches and vegetative leaf buds have not been severely wounded.