Caring for trees in the cold

Trees add much more than just aesthetics to our landscapes and homes.

“Trees provide a wide range of economic, environmental and social benefits to our communities and it’s important to care for them properly,” said Mac Martin, Texas A&M Forest Service Urban Forester. “Trees need care and maintenance in order to survive and flourish, especially young or newly planted trees.”

Young and newly planted trees need particular care and attention so they can begin their long lives in a strong and vigorous manner that greatly increases their chance of not only survival, but to provide their benefits in an optimal and efficient manner.

This is especially true in winter, said Martin.

“Even though Texas is not known for harsh winters, the winter season can still be tough on all, trees included, as evidenced by Winter Storm Uri in February 2021,” said Martin. “Harsh conditions like cold winds, bright sun, bitter ice, snow and frost can pack a punch.”

During the cold months of winter, even here in Texas, there are many factors or conditions that will cause damage to a young, newly planted tree. Luckily, there are ways to protect vulnerable trees, so they remain viable and healthy long after the cold of winter has passed.

Follow these four essential tips to help protect young or newly planted trees from winter damage:

Watering – Newly planted trees don’t have extensive, well-established root systems, meaning they are usually shallower and not able to use soil moisture as effectively as more mature, healthy trees.

Water helps insulate both the tree and the soil. Moist soil will be warmer and a well-watered tree will be less susceptible to freeze damage. If a hard freeze is forecasted and soil moisture is low, it is best to water the tree before freezing temperatures occur.

Recommended watering schedules vary by region but, in general, should be followed through October and early November. For hardwood species that go dormant, watering can be reduced to once or twice per month, depending on rainfall, in winter months. Watering should be done early in the day so the tree has time to absorb it before the drop in nighttime temperature.

Mulching – Mulch is a simple and inexpensive way to winterize a young or newly planted tree. In addition to providing a barrier of protection against wind, freezing temperatures and frost, mulching helps trees retain heat from the soil.

Repeated freezing and thawing of the soil can cause soil to expand and contract, which in turn can cause root damage. Mulch acts as an insulator preventing cold air from penetrating the root zone of newly planted trees and keeping soil temperatures higher, which helps to keep the trees warmer during the winter.

A 2- to 3-inch layer of mulch should be spread around the base of the tree, at least the width of the root ball on a newly planted tree taking care to keep the mulch about two inches away from the tree’s trunk.

Wrapping – The sun can be quite damaging to a young or thin-barked tree on a cold winter day by heating up the tree’s bark, stimulating activity. When this happens and then passing clouds drift by, blocking the sun, bark temperature can drop rapidly, damaging or killing that active tissue. The resulting damage is called sunscald.

Sunscald can be avoided in these vulnerable trees by wrapping the trunk for winter protection. Wrap the bark of susceptible trees in late fall with either tree wrap tape, plastic tree guards or similar light-colored material. These can be found in garden stores.
Remove the wrap in the spring after the last frost to avoid insects living under the material during the summer.

Pruning – Winter, or the dormant season, is the best time to prune trees. Especially young or newly planted trees that may require some pruning to train growth away from conflicts.

Most light pruning or pruning that removes dead, damaged, weak or diseased limbs can be done at any time during the year with little effect on the tree, but if live tissue is to be removed it is best to wait until mid- to late winter. Generally, wound closure is maximized if pruning takes place before the flush of spring growth. Heavy pruning of live tissue just after the spring flush should be avoided, especially on weak or stressed trees.

For more information about proper pruning or to find a certified arborist, visit https://www.treesaregood.org.