Preparing new plantings for winter

Newly installed landscapes are particularly susceptible to the cold New England winter weather. Even mature plants cannot sustain great damage if conditions are bad enough. Remember last winter the devastating losses of mature Rhododendrons. One of the prime reasons for the loss was lack of sufficient moisture to get through the winter. If a winter is colder and longer than typical, even healthy, well-watered plants can suffer, but newer planting with more shallow root systems are the most vulnerable.

A few measures help to insure success. The most important is to insure that the plantings are getting enough water right up until the time the ground freezes. Woody trees and shrubs need about one inch of water per week. Hand water if we have a dry fall / early winter. Another measure to prevent winter damage is to mulch all plantings. One to three inches of mulch is the correct depth to insure that water penetrates down to the root system, while from above protecting evaporation. Too much mulch is always bad for plants.

Commercially available antidesiccants can also prevent loss of moisture through foliage on evergreens during the winter, especially on plants that are in open windy sites.

Winter can also bring physical damage to plantings when the weight of snow and ice breaks stems and branches. Avoid planting under roof drip lines, or in the line of fire from snow sliding off roofs. Loosely tying plants with twine help shed snow and prevent interior breakage. Latticed frames placed over plantings help absorb heavy loads. Never cover plants with plastic, non-breathing material, or anything to restrict airflow.

Wait! Don’t Cut That Back!

Most perennials look pretty beat at this time of the year, wait until spring to remove old foliage on some perennials. Most crucial is the Tree Peony, which unlike its herbaceous relative, forms a woody stem with next years buds. If you cut back this woody stem, you loose the whole plant. It is not much to look at in the winter, but rewards you in the spring. Liriope is an evergreen grass like plant that will provide winter interest if left uncut. Its leaves will look decent until about April, when they should be cut back to let the new growth come in clean. Christmas Ferns grow in the same manner. Helleborus, left intact, is another plant with hardy foliage. The flowers will start blooming in late winter and new foliage emerges. Once that occurs, cut back the older foliage.

Other plants to consider leaving untouched for the winter are those with ornamental seed pods such Siberian Iris, Baptesia, and sedum, or those that provide winter food for birds, such as Rudbeckia, Asters, and Echinacea.