Preparing trees and shrubs for winter

JACKSONVILLE, Ill. — The leaves are dropping off trees, and many of us are putting our gardens to bed for winter. While preparing the garden for winter, spend a little time preparing your trees and shrubs. Doing a few things this fall can help protect our trees and shrubs from winter damage.  

Watering doesn’t stop when summer is over

Given the dry conditions we’ve had this year, make sure trees and shrubs have adequate water. Continue to water trees and shrubs (if we don’t get enough rain) until the ground freezes. Since temperatures are cooling and plants are using less water, they won’t need to be watered as frequently as in warmer parts of the year, maybe every other week.

Providing adequate moisture to trees and shrubs will help reduce their stress and damage from winter weather. This is especially important for newly planted trees since they are unlikely to have an extensive root system and evergreens.

Evergreens keep their leaves year-round and are more likely to suffer winter desiccation (also known as winter burn). Desiccation is caused when plants lose moisture faster than they can take it up. This will result in discolored and damaged plant leaves and tip dieback. Having well-watered trees and shrubs and adequate soil moisture can go a long way in preventing winter desiccation. Additionally, roots surrounded by moist soil are less likely to suffer cold injury compared to those in dry soils.

Protection from desiccation

In addition to adequate soil moisture, evergreens in exposed sites may benefit from additional protection to prevent winter desiccation. These plants can be wrapped loosely in burlap, or a windbreak can be constructed.

Anti-transpirants are commonly recommended to help prevent desiccation in evergreen plants. These products are wax-like materials sprayed onto plants’ leaves to slow water loss. Before applying a product, make sure to read the label. Some products should only be used on broadleaf and needled evergreens, not on evergreens with scale-like leaf foliage such as arborvitae.

While anti-transpirants may help a little in preventing winter desiccation, they aren’t a replacement for making sure your plants are well-watered and protected if they are in exposed locations.     

Mulching plants

Mulching trees and shrubs is also beneficial when preparing them for winter. Mulch will help retain soil moisture and help prevent rapid fluctuations in soil temperature. Organic-based mulches, such as wood chips, are preferred because, in addition to the above benefits, they will also slowly break down and add nutrients to the soil.

When applying mulch, put down a 2- to 4-inch-deep layer, ideally out to the tree’s drip line. Additionally, make sure it is not piled up on the plant’s trunk (mulch should look like a donut, not a volcano). Mulch piled up against a tree trunk creates an ideal environment for diseases, insects, and rodents.

Don’t be too quick to prune

While cleaning up the garden, there is often a temptation to prune trees and shrubs. Don’t be in too big of a hurry, though. Pruning in late summer and fall will often encourage plants to produce new growth. This new growth won’t have enough time to harden off before winter arrives and will be damaged or killed. The only pruning that should be done on trees and shrubs in the fall is to remove dead or damaged branches. Otherwise, wait to do any other pruning, such as removing crossing and rubbing branches, until the trees are fully dormant (winter).

When watering trees and shrubs, provide enough water to moisten the soil 6 to 8 inches deep. This will provide moisture to most of the plant’s feeder roots.