Help plants survive the cold
By Pamela Doan
These extended warm days have been wonderful this fall, and many gardeners have been out there enjoying extra time in the landscape. Freezing temperatures are closing in this weekend, though, and there are some plants that could use help getting through the winter.
Winter brings unique challenges to plants. Among the issues that can affect whether they make it through the season in good shape are weather-related like snow and ice, and also wildlife looking for food.
Snow and ice
Heavy snowfall can damage tree limbs and break branches on shrubs. Ice buildup can be more damaging even than snow, depending on when it hits during the season. Trees like arborvitae with thin, crotched branches are most vulnerable.
It’s not too late to prune weak branches or branches that threaten buildings or overhang walkways. If you’re not sure, call an arborist for an assessment.
Rabbits, mice, voles and deer all can cause damage in the winter, too. When food becomes scarce, they will eat almost any green thing they can find. During winter, deer in high-browse areas will eat evergreens that might go untouched during warm months. Heavy snowfall can provide a cover for animals, too. Voles will girdle the tree by chewing a ring around the trunk that will destroy it.
Consider fencing any valuable trees in the landscape if you’ve had deer browsing problems in the summer. The nasty-smelling sprays won’t work in the winter, and it’s too late to protect a tree if you notice it’s being eaten after the ground is frozen. Last winter the snow was high enough that deer managed to reach over the 6-foot fence around young arborvitae in my yard, but it had been a successful deterrent in previous winters.
To keep voles and rabbits from damaging plants, wrap the base with a metal cylinder or fine mesh hardware cloth that rises above the level of the snow.
Plants don’t grow when the soil has too much saline, and the salt we put on our driveways and sidewalks to melt ice in the winter can affect plant roots. Go easy on salting by mixing commercial ice melt with cat litter or sawdust. Be careful when spreading it to try to keep it on the driveway and off the lawn, and avoid planting anything that is particularly sensitive to salt near areas that require ice melt.
Plants dry out during winter from the effects of wind and sun and frozen ground that keeps water from getting to the roots. Evergreens are the most susceptible to desiccation and show signs by browning and dropping needles. Avoid planting evergreens in exposed areas like alone on a hilltop in the first place for the most success.
Trees do best when they go into winter well watered. They need 1 inch of water per week. It’s not too late to give plantings their 1 inch on days when the temperatures are above freezing.
Mulching helps plants, shrubs and trees retain water during winter. When temperatures are dropping is the best time to add mulch around the base of trees and shrubs and over the flowerbeds and garden. Don’t pile mulch around the trunks, though; this gives voles and mice a place to burrow and hide. You won’t notice their damage until it’s too late, when you remove the mulch in the spring.
When the ground freezes and then subsequently thaws, it contracts and expands and re-freezes. The movement pushes up roots and bulbs and anything else in the ground, exposing them to frost and damage. Here again, mulch is the answer. It helps to regulate the ground temperature and protect plant roots. Straw, wood chips or shredded leaves all work well as organic mulches.
To wrap or not
Last, but not least, when should plants be wrapped? We’ve all seen shrubs wrapped in burlap in a yard. Is it really necessary? It’s hard to tell, actually. On the one hand, any planting that is hardy for our area should be able to survive the winter without an extra layer of protection. In general, our winters are warming. Due to climate change, we’ve had warmer than average winter temperatures for many seasons now. However, climate change has also brought on more extreme weather events. It’s more likely that we’ll have a colder than normal spell but warmer temperatures on average, leaving plants vulnerable.
In general, it isn’t necessary to wrap hardy plants, but consider protection for any vulnerable or young plantings that are worth the time and investment.