Our cold and snowy winter has created a lot of discussion on a variety of subjects from roads to roofs. Our landscape plants in our yards have not received much attention, although there are concerns because of the recent winter weather.
Ward County is in USDA plant hardiness Zone 3. Plants adapted to Zone 3 should tolerate the minus 30 degree nights that we have received.
Marginally hardy plants that are not Zone 3 can often survive short periods of the extreme cold temperatures, but persistently frigid conditions could cause damage.
Cold is not the only factor in determining hardiness. Other factors include fall soil moisture levels, whether the plant site protected or exposed, and additional stresses from insects or diseases. The hardening-off process in the fall and the dehardening-off process in the spring can have a greater impact than the cold in midwinter on the survival of landscape plants. If temperature ranges in the fall or spring are extreme winter damage on some species can be extensive. This type of damage is commonly seen on our conifers.
A good snow blanket can protect many plants. Snow is great insulator from the cold and temperature fluctuations. Some of the problems associated with snow can be the things that happen under the snow. Mice feeding on young trees at ground level under the snow can be very destructive. A barrier should be placed around young trees in the fall to prevent this type of damage. Rabbits and deer feeding on young trees above the snow level can also be a problem. Repellants may help reduce this issue. Snow removed from roofs of our homes can be very damaging if left on foundation shrubs. Snow mold on lawns is more common after a winter with extensive snow levels. Lawns with snow mold infections should be raked early in the spring.
Generally our plant material, especially our trees, should benefit greatly from the fall and winter moisture that the area has received.
Mike Rose is Extension agent for the North Dakota State University Extension service in Ward County.