Drying winds can steal moisture from arborvitae and other conifers. But wrapping them in burlap isn't a sure cure.
Winter can be a tough time for plants. The extreme temperatures and brisk winds can damage the stems and leaves of plants.
Deciduous trees lose their leaves, which can limit some of the damage. But conifers don't have that luxury. They continue to lose moisture through their needles all winter.
Spruce, arborvitae and other popular evergreens are particularly susceptible to wind damage. As cold, dry wind flows through their needles, it sucks away moisture. Often, the damage won't be visible until spring. When the trees begin to grow again, areas that were dehydrated can turn brown and die.
Here are a few things you can do to help your evergreens get through winter in the best shape possible.
Wrapping evergreens in burlap to protect them from the ravages of drying winter winds has become an accepted fall chore in many Minnesota households.
Unfortunately, it's not a good tradition to keep because burlap wraps aren't very effective. They may even be detrimental to the health of conifers.
When it's wrapped around a tree, burlap acts like a towel, wicking away moisture and making the tree even drier. In addition, burlap wraps limit air circulation around the branches, which can lead to disease. The wraps also may cause conifers to warm up too early in the spring, which can trigger new growth that could be vulnerable to late frosts.
There are other, better ways to protect your trees.
One of the best ways to prepare your trees for the cold, drying winter winds is also the easiest: water.
A tree that's well hydrated heading into winter has a better chance of coming through the cold unharmed.
As winter approaches, plants take up less water. But that doesn't mean they don't need water. So don't give up. Unless there's a good, soaking rain twice a week, continue to give each tree about 5 gallons of water a week until the ground freezes.
You can use burlap to create a wind barrier, which will help prevent trees from drying out.
Just pound some metal stakes or fence posts into the ground about a foot from the edge of the tree's canopy. Stretch burlap between the posts to make a fabric wall, which will block the wind. If possible, the windbreak should be about as tall as the tree.
There are products called antitranspirants that you can spray onto your conifers to prevent moisture loss. Usually made from waxes or plastics, they are designed to coat the tree's leaves, supposedly blocking small pores. However, antitranspirants tend to be ineffective because as winds bat the branches around, the chemicals tend to wear off.
Jeff Gillman, an associate professor of horticulture at the University of Minnesota, is the author of several gardening books.