UW Extension Offers Resources on Caring for Landscape Plants Damaged by Mild Winter, Yo-Yoing Temps

For Wyoming residents concerned about how their landscape plants will cope with a dry, windy and mild winter followed by temperature swings, University of Wyoming Extension has published a new online brief.

In anticipation of a predicted cold snap, gardeners and homeowners also are encouraged to reach out to their local extension offices with questions or concerns.

"We've had unusually warm and dry weather in many parts of Wyoming this winter," says Jennifer Thompson, UW Extension horticulture specialist and author of the brief. "If this trend continues and brings with it our typical western region yo-yoing temperatures -- warmer spells followed by deep-freeze events -- we are likely to see a variety of effects on plants as spring and summer roll around."

In early spring, perennial plants are beginning to break dormancy. At this point, they become more vulnerable to cold damage.

Cold damage can affect the flowers, leaves, and woody stems and branches of trees, shrubs and flowering plants. Effects vary depending on species and conditions, but certain types of damage are common when mild winter weather is followed by a cold snap.

Newly planted or thin-skinned trees can be at risk of trunk damage caused by sunscald. As sun warms a tree's bark, its cells become more active. As the temperature drops sharply at night or during a cold spell, these active cells can freeze, causing tissue damage on the side of the tree facing the sun.

Sunscald can be fatal in some cases, but prevention measures exist, and trees often successfully partition off this type of damage if it is not too severe.

Especially in years with severe temperature swings, it's not unusual for flowering fruit trees to suffer cold damage. This often results in little to no fruit set during the upcoming growing season. However, it doesn't hinder future fruit production.

Many healthy perennial plants that sustain early cold damage will outgrow it as the season progresses. Some spring bulbs that emerge earlier than usual may remain unscathed, in some cases freezing at night and defrosting in the morning without ill effects.

If bulb flowers and foliage are partially damaged by the cold, it is not recommended to remove them. Instead, gardeners are advised to leave them in place until they naturally die back for the season.

If a tree appears to have suffered cold damage to branches or stems, it is best to monitor its response rather than immediately reaching for the pruning shears. Trees and shrubs often put out a new flush of leaves and have reserve buds that begin growing if primary buds are damaged.

In many cases, landscape plants can recover from cold damage, especially if they receive plenty of water and nutrients during the recovery period.

"Whether we get some untimely deep freezes after plants have come out of dormancy this year, or the next, or the one after that, we hope that this article will help you determine what has happened and what steps you can take to help plants recover," Thompson says.

To read the full article, which also offers tips on caring for trees and shrubs affected by winter desiccation, visit https://bit.ly/warm-winter-wyoming.

For advice on how to handle specific situations involving possible cold damage, contact a local UW Extension office. Contact information can be found at https://bit.ly/uwe-counties.

About University of Wyoming Extension

University of Wyoming Extension serves Wyoming communities by helping residents apply university research and resources to practical problems. Since 1914, UW Extension has provided educational programs and tools to the state's 23 counties and the Wind River Indian Reservation. From 4-H programming and pesticide safety education to food preservation and nutrition courses, UW Extension upholds the university's land-grant mission by offering learning opportunities for people of all ages. UW Extension staff help Wyoming residents boost agricultural production, care for lawns and gardens, cultivate future leaders, support individual and community well-being, and develop thriving businesses. To learn more, visit https://www.uwyo.edu/uwe or call (307) 766-5124.