By Bill Snyder
OSU Ext. program assistant
Winter assaults your plants from many sources. But if you’re prepared, you can limit the damage.
During freezing temperatures, water tends to move out of plant cells. When temperatures move back above freezing, the water moves back into cells. Damage can occur if cells are dehydrated for prolonged periods. Fall watering can prevent injury by providing a reservoir for rehydration during winter. Also, mulch applied over the root zone after soil temperatures fall below about 40 degrees will help preserve moisture and protect roots from severe temperature changes.
Strong winter winds tend to dehydrate evergreens and cause injury when moisture is lost to the atmosphere faster than it can be replenished through the roots. Foliage that loses a large amount of water may eventually dry out, turn brown and die. Providing a watered and mulched root area will help replenish the moisture. In some instances, a wind barrier may be necessary. Spraying an anti-desiccant throughout the winter when temperatures exceed 45 degrees can help prevent damage.
Multistemmed evergreens like junipers and arborvitae can be damaged by a heavy accumulation of ice or snow, but that can usually be prevented by tying the stems together with twine.
Rabbits and mice often damage young trees and bushes by feeding on bark during winter, especially during prolonged heavy snow cover. Typically rabbits feed on bark above the snow cover while mice feed near ground level by tunneling under the snow. The feeding can result in girdling of the tree or shrub. The most effective preventative is to wrap the trunk and lower branches with screen wire or hardware cloth. Bury the screening below the ground and let it reach higher than the potential snow line. Removal of snow from around the plant may also be necessary.
Deicing salts can also damage plants. Limit damage by using only amounts necessary to loosen and remove ice and snow with a shovel instead of trying to completely melt the ice. Try mixing it with an abrasive like sand to limit concentrations. Avoid placing salt- laden snow around trees and shrubs.
To minimize damage from salt on roads, water the area heavily as soon as the ground thaws to wash the salt from the root zone.