This winter has brought cold temperatures, dropping into the single digits, that may have damaged your plants. You may notice your evergreen trees or shrubs are displaying leaves that have either turned brown or are falling off. During the colder winter months, your evergreen plants can become injured when ice forms inside the plant tissue and cells or by water loss, through a process called transpiration. The entire plant or just small part of the plant tissue and stems can be affected. This damage is greatest in plants that are exposed during periods of strong winds and on bright, sunny days. This kind of damage is common on: Hawthorns, Gardenias, Tea Olives, Boxwoods, etc. Even leafless shrubs may show signs of damage this spring.
What can you do?
- While you may think your plants look better if you prune off the dead leaves and twigs now, you’ll only be exposing the healthy, undamaged lower growth to the threat of more damage in the cold weather of March and April. Wait to do your pruning until your plants start showing new growth.
- Your trees and shrubs will need fertilization this spring, they are already nutrient starved since their greatest source of winter and spring food is raked and removed or blown away each fall, leaving the soil lacking in the rich organic material that the decomposition of leaves creates. Fertilization will help in a couple of ways: The organic material will help your plants push any new growth past the previously damaged tissue, and heartier, healthier plants will be more able to recover from injury or stress.
In Colorado, the average date range for your risk of frost is from October 2nd through May 4th.