Protect Your Landscape From Winter's Ravages
New Hampshire's winter weather will be arriving anytime but before
you settle in don't forget that there may be a few late chores to attend
to.
Do you have spring flowering bulbs that somehow did not get planted earlier this fall when they should have? If you are in this situation, plant them anyway. Even though the ideal planting time has come and gone, your bulbs will be better off in the ground than in any other place. These bulbs may take a year or so to adjust themselves but eventually they should come around.
Mulches should be applied to new plantings of herbaceous perennials and bulbs to strawberries, and to tender trees or shrubs as the ground freezes. The purpose of the 2” to 3” layer of mulch is to prevent sudden temperature changes, thus reducing the possibility of soil heaving due to alternate freezing and thawing. Snow cover makes the best winter protection, but it is an unreliable mulch source since it can't be depended upon. Mulches to use include: salt marsh hay, weed-free straw, bark chips, evergreen boughs, pine needles or shredded leaves. Remove mulches slowly when growth commences in the spring. When yellow leaves appear on herbaceous plants the mulch can be removed. Keep in mind that soil temperatures will warm more slowly in the spring if the ground is mulched.
Because they hold their leaves through winter, evergreens are more susceptible than other plants to injury. This is particularly true with broadleaf varieties -rhododendrons, azaleas, holly, etc. Exposure to wind or hot sun can cause the following to give off water (transpiration) that cannot be replaced when the soil is frozen and the roots are inactive. The result is leaf scorch or winter injury. This type of damage often occurs on warm days in early spring before the soil has warmed up.
An important consideration for winter protection is the plant's location in your landscape. If you have wondered why some of your shrubs show winter injury while others seem unaffected, you may want to take a closer look. The damaged shrubs may be in a sun or wind-exposed location. Protective screening can help to limit the amount of exposure. Anti-desiccant sprays can also be used. These are helpful in slowing down the rate of transpiration by coating the foliage with a layer of plastic or wax material. However, one application of an anti-desiccant is not enough. Anti-desiccants are most effective when applied two to three times: in late fall or early winter, again during a January thaw, and if possible, a third time in late winter.
Simple shade screens or wind breaks for additional protection can be constructed of burlap secured to wooden stakes. Snow fencing or lath will also provide protection. Plastic should never be used since all you're doing is creating a mini-greenhouse which will cook your plants, Shades and screens should remain in place through early spring, until the soil temperature has warmed sufficiently to allow for water uptake by the roots.
Sunscald is a form of winter injury that damages the bark of many young trees. Tender bark on the south side or beside a sun-reflecting wall can warm up considerably during the day. When the temperature drops suddenly at sunset the bark may split. Insects and diseases can enter these splits, leading to further trouble. Wrap the trunks of young trees with a commercially available paper or plastic tree wrap to keep this problem from developing. Take the tree wrap off in spring for the summer months. A good rule of thumb is to put wraps on at Thanksgiving and take them off at Easter.
Heavy snow build-up on plants can also bend and break branches. Snow fence, lath, or staked burlap screens are helpful in avoiding this type of damage. Multi-stemmed or evergreen plants (yews, arborvitae, junipers) can be tied with cord to prevent splitting. Tying should be done before the first snowfall. Twine or soft rope should be fastened at the base of the plant and wound spirally upward to the top, and then back down in reverse. This compresses the shrub.
Lastly, if the soil is dry, water one last time just before the ground freezes - usually in late November or early December. This is especially important when we have a dry fall like this year's.
Call the UNH Cooperative Extension's Family, Home & Garden Education Center 's Info-Line toll-free at 1-877-3984769 for "Practical Solutions to Everyday Questions." Trained volunteers are available to answer your questions Monday through Friday from 9 am to 2 pm .
By Margaret Hagen, UNH Cooperative Extension Educator, Agricultural Resources, Hillsborough County