Overwintering Outdoor Plants
Many landscape plants die during the winter but there are steps you can take to lower the mortality rate. Even though temperatures drop, keep watering your landscape until we have a hard frost. Stressed plants have lesser chance of surviving at any time of year but especially through the winter.
Broadleaf evergreens such as azaleas and rhododendrons become dessicated much more easily than coniferous evergreens. Buy an anti-dessicant (Wilt-Pruf, Vapor Guard, and Transfilm are the most common) and spray the leaves when daytime temperatures start falling below fifty degrees, usually mid to late fall. Be sure the temperature is above freezing and there is no threat of rain or frost within 24 hours. Reapply in February.
I often see coniferous evergreens wrapped in burlap to protect them from salt spray. This has to be one of my pet peeves. The reason for planting evergreens is seeing green in the gray months. If you can’t see them, what’s the point? Plant something else, like ornamental grasses, that do not suffer from salt intolerance and will be beautiful during the winter. You want to see plants that will lift your spirits.
Young trees often suffer from sunscald (bark splitting) when the temperature drops suddenly. The best preventive is a burlap wrap around the bark for the winter. Be sure to remove it in Spring after temperatures rise into the fifties.
Hopefully, you have mulched perennials that were planted this year. Mulch mitigates the temperature swings that we see in the freeze/thaw cycles and thus is a help in preventing plant heaving. If you notice plants whose roots can be seen, get out your shovel if the ground isn’t frozen. If it is frozen, cover the roots with soil, mulch, straw or whatever you can find so that the roots do not dry out.
Do not prune your roses now unless they have long branches that will whip around in winter winds. Even then, prune no lower than three feet. Rose pruning is best done in early spring when you see leaf buds.