Winter’s chill can challenge young trees and fruit trees, but the right preparation helps them weather freezing temps. Start by inspecting and pruning your trees, then spray them with an anti-desiccant to retain moisture. Prep the surrounding soil by watering and mulching, then cover your trees with barriers like a tarp or tree guards.
Of course, a lot can go wrong in the process. Unsure about pruning or wrapping your trees together to protect them against frigid temps? Let a local pro help.
Here’s how to protect trees from a freeze, step-by-step.
Which trees need protection?
You mainly need to protect fruit and citrus trees, palm trees, and broadleaf evergreens. You also need to protect all newly planted trees.
Sarah Vogel, extension educator of horticulture at the University of Illinois Extension, warns that “some trees are more susceptible to broken branches in winter conditions, like multi-stem trees, upright evergreens, and especially trees with included bark from co-dominant stems or narrow branch angles.”
A codominant stem is one of two or more main stems in a tree that are similar in size and arise from the same point on the trunk, often creating a “V” shape. This is a weak structure that doesn’t handle storms very well.
Vogel also notes that boxwood, arborvitae, and other evergreen species are susceptible to winter burn and water loss. Furthermore, thin-barked trees like maple, ash, linden, apple, and peach are likely to suffer from sunscald and frost cracking. Older trees with thick bark are less likely to sustain freeze and frost damage.
Treat your trees
Prune as necessary: Vogel advises preparing your trees for storms before it’s too late and pruning deciduous trees while they’re young. “Remove codominant stems and promote an appropriate scaffolding structure,” she says. As I explained above, these stems are two or more main stems in a tree that are similar in size and arise from the same point. If your tree is mature, don’t remove the codominant stem, but call a pro for professional cabling.
“Avoid pruning in late summer or fall, as it promotes new growth that cannot harden off before winter,” Vogel continues. “This can lead to frost damage dieback on branch tips.” If branches do break, it’s not too late to fix the damage. Vogel’s guidance is to prune them back to the main branch or trunk and seek pro help to prune back limbs of larger trees.
Bring container trees inside: If you have any small trees in containers, the solution is simple: bring them inside where they will be safe from frost.
Spray outdoor trees: “Anti-desiccant sprays help retain moisture and protect plants from some fungal diseases,” Vogel says. These sprays, commonly used on broadleaf evergreens, make a thin, invisible coat on the leaves to thicken their outer layer and help them retain moisture. Think of it as a winter lotion for trees and plants.
Choose a warm, dry day in the late fall to early winter, when there’s no rain or snow anticipated for the next 24 hours. Choose a time when temperatures are 40 to 50 degrees Fahrenheit, but frost has already occurred a few times. Use a battery-powered sprayer to spread the solution more easily, especially if you’re dealing with large or multiple trees.
Treat your soil
Expose the soil: Remove weeds and turf from under the tree in the fall. Bare soil is best for absorbing and reflecting heat.
Water deeply: Well-watered trees that aren’t under drought stress are less likely to get damaged by frost cracking and sunscald, and moist soil absorbs more sunlight and heat. Vogel notes that fall watering is particularly important when there hasn’t been much rainfall.
“Watering is recommended when the soil is dry 4 to 6 inches below the surface, air temperatures remain above 40°F, and the ground is not yet frozen,” Vogel says. Don’t let ice crystals form on the leaves, because they might dehydrate them.
However, Vogel recommends watering your lawn when the ground thaws briefly during warmer winter days. This reduces the damage of winter burn.
She also stresses focusing on depth rather than frequency, which varies by tree, soil type, and climate. Some young trees need water every week, while newly planted trees need it even more often. On the other hand, mature trees do best with a less frequent, deep soak.
“The goal is to moisten the soil 8 to 12 inches deep beneath the canopy, where most absorbing roots are located,” Vogel says. “Soaker hoses, drip irrigation, or a slow trickle from a hose are effective methods to ensure moisture reaches the root zone without runoff.”
Water the roots of large trees just outside the drip line, but not at the trunk. Check how well the water absorbs. If you notice that it pools or runs off, your soil may be compacted and benefit from aeration.
Add mulch: A 2- to 4-inch layer of organic mulch like wood chips retains soil moisture and reduces competition from turfgrass.
“Mulching not only conserves water but also insulates roots from sudden temperature fluctuations as winter approaches,” Vogel says. She advises extending your mulch to the drip line if you can and keeping it a few inches away from the trunk to prevent rot.
While wood chip mulch is the most effective, you can also use shredded leaves or compost. However, watch out; too much mulch attracts unwanted visitors like rodents, insects, and fungi.
Use tree covers
Cover your trees: Cover young or small trees before the freezing weather hits to trap warmth. It protects against winter burn, frost cracking, and sunscald. Trees that suffer winter injury year after year become the most damaged, so do what you can to prevent it.
Drape your trees with burlap, sheets, or tarps that extend to the ground. Reduce contact between your trees and your cover with a frame or stakes, then use twine or clothespins to secure it in place.
Alternatively, pile clean soil a foot or two high on the trunks, or use plastic tree guards. Plastic tree guards have an extra advantage: Griffin Dill, extension professional at the University of Maine, recommends them for protection against rodents.
“If using tree wrap, apply wraps in November and be sure to remove them in April,” says Vogel. “Leaving wraps on all year can cause damage or restrict growth.” You should also wrap your tree if the weather becomes freezing after new leaves have begun growing in the spring.
Use grow tubes on young trees: Grow tubes are basically tiny greenhouses that nourish young trees and protect them from freezing. They remain until the trees outgrow them.
Wrap small trees together: Wrapping trees together protects them against snowstorms. If you’re dealing with small trees like birches, wrap them together with strips of strong cloth, carpet, or nylon stockings. Wrap snugly but not too tightly.
Unwrap the trees again in the spring to allow their stems to grow freely. If you want to wrap larger trees, they’ll need professional cabling.
FAQ
If you really need to provide warmth, for example, to saplings, a heat lamp with a 100-watt bulb is another option. However, it can burn your tree or sapling if it touches it and is a significant fire risk, so be really careful.
Vogel warns that removing snow loads by shaking branches can lead to further damage in frozen, brittle branches.
Instead, “Gently remove snow by using a broom and sweeping upward, but do not stand under the branch,” Vogel says. “It is best to wait for a warmer day or until the ice melts. Trying to remove ice just causes further damage.”
Inspect your trees. Look for wilting, discolored, distorted, or falling leaves as well as split bark.
Ease your trees through the winter freeze
There are various tree protection methods, but ultimately, they take valuable time (and sometimes, even heavy lifting). Let someone else handle caring for your lawn and yard this fall while you “chill out.” From gardening to clearing fallen leaves to your final mow, Lawn Love’s pros have your back.
Main Image: Trees wrapped in plastic for freeze protection. Image Credit: Michele Ursi / Adobe Stock
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