Gardeners can, to some degree, help plants adapt to winter. For instance, reduce the amount of nitrogen fertilizer applied after mid-July and stop all fertilization by late summer. Also, do everything you can to ensure that your plants enter the autumn season healthy but not growing too fast.

Make sure the soil in which evergreens are growing is well-watered in mid to late autumn, before the soil freezes. If the landscape where evergreens are located is in a dry site, sandy soil, or under the overhang of a roof, also make sure that the soil is well watered in midwinter if the temperature is above freezing.

Here are some other steps you can take to decrease the likelihood of winter injury to plants:

• Plant on the north side. Choose a location for marginally hardy plants with a northern or eastern exposure rather than south or southwest. Plants facing the south are more exposed to the sun on warm winter days and thus experience greater daily temperature variation.

• Mulch. Apply a layer of mulch, 3 to 4 inches (7.5-10 cm) deep, after the soil freezes to keep the soil cold rather than protect the soil from becoming cold. This practice reduces injury from plant roots’ heaving (coming out of the soil) because of alternate freezing and thawing. Plants that benefit from this practice include perennials, alpine, rock garden plants, strawberries, and other shallow-rooted plants. A mulch maintains a more even soil temperature and retains soil moisture.

• Wrap with twine. Plants such as arborvitae, juniper, and yew often suffer damage from the weight of snow or ice. Prevent plant breakage by fastening heavy twine at the base of the plant and winding it spirally around and upward to the top and back down in a reverse spiral. This technique is more necessary as plants become larger and begin to open at the top. Be certain to remove the twine during the growing season.

• Use burlap screen. Stretch a section of burlap around three stakes to protect young or not fully hardy plants from the south, west, and windward exposures. A burlap wrap with stakes protects plants from the drying winter sun and wind as well as drift from deicing salts applied to drives and streets. Wrap most of the plant, but leave some of the top of the plant exposed. Evergreen plants need light, even in winter.

• Prevent drying. Narrow and broadleaf evergreens lose moisture through their leaves in winter. Plant roots can’t absorb moisture from the soil in winter because the soil may be frozen and therefore can’t replace the moisture the leaves lose. The foliage desiccates, turns brown, and may drop, which can be serious with evergreen azalea, holly, boxwood, and rhododendron. Make sure that evergreens are properly watered throughout the growing season and into the fall. Decrease watering slightly in fall to encourage hardening off, and then water thoroughly in October and continue until soil freezes.  ....read more