Q: Bone-chilling cold has me inside, but what will happen to my shrubs and trees? What can I do to help them now?
A: Our region has been experiencing wicked cold spells and our plants may be suffering more than the complaining gardeners. Fortunately, at the upper elevations, where temperatures were the lowest, a recent snowfall provided an insulating and hydrating blanket for many plants and trees. The recipe for the most dangerous winter conditions for our plants are:
* A warm moist period that encourages early bud swelling;
* A sudden temperature drop to dangerous lows with bright burning sunlight that can split tree bark;
* Lack of moisture in the ground that can cause damage to evergreens and deciduous plants;
* Drying winds and frozen soil that cause winter burn on evergreen foliage;
* Sharp freezes and thaws that can cause frost to heave plants out of the ground.
We have so far avoided the worst of these winter dangers. Most of our plants appear to be still in their winter dormancy, which offers a certain amount of protection in itself. You will notice your rhododendrons with protectively rolled leaves, and, luckily, the deciduous trees have no foliage to hold heavy ice loads.
As soon as the bad weather has passed, make an inspection of your trees. Smaller trees with thin and tender bark are the most likely to show freeze cracks. Look for deep vertical wounds where the sun strikes the tree. These wounds can bleed as spring sap rises and weaken the tree.
Keep a wounded plant well-watered and watch to make sure the wound heals on its own. You can cover the trunk with tree wrap to prevent further damage but remove it in spring. Check your small shrubs and perennials for frost heaving and if this is evident, carefully replant and cover with mulch.
Contact Pat Lea at lea.pat@gmail.com.