Wow! It has been pretty cold out there the last few days. It seem like the winter temps. here on Cape Cod are all over the map. For example, Jan.17: Low of 11 and high of 23. Then for the rest of the week it’s in the 40’s. Huh? Okay, then on the 24th, I’m sure we all remember: a whopping 2 degrees for most of the day with a high reaching all the way to 11! BRRRR! But then wouldn’t you know it, the rest of the week was temps above freezing. Good ‘ol Cape Cod weather.
Well this fluctuation actually takes it’s toll on the trees and shrubs. Especially during drastic winters, such as this one has been. Very often in the early spring many evergreen plants will be spotted with brown and wilted leaves. This damage is often called winter burn. Winter burn injury is leaf damage that is caused by cold winds which dry out the leaves. Winter burn injury can take place whenever the soil freezes and wintry winds blow, drawing moisture from leaves. Plant roots can not uptake water from frozen soil to replace the losses experienced in the leaves.
Winter burn can also occur when the air temperature periodically rises. The warmer temperature causes the leaves to begin the process of transpiration, the release of moisture through small pores on the surface of the leaf. The longer these conditions exist, the more moisture is lost and death of leaf tissue results. Plants that hold their leaves (evergreens) over the winter are vulnerable. Broad leaf types are more susceptible than the needle type evergreens due to the larger surface area of their leaves. This kind of damage is a common problem here on Cape Cod as our winters tend to be quite windy with unpredictable temperatures.
To prevent this damage make sure you water your evergreen trees and shrubs into the fall until the soil freezes.
You May also want to create a barrier around plants that are susceptible to burning, including wrapping them in burlap.
Here is a list of some (but not all)evergreen plants that can be susceptible:
*Japanese Pieris (Andromeda)