Winter injury is observed in decorative plantings

Submitted by: Kelly Piccioni, Sara May, Leah Fronk, Penn State Extension

Spring is planned and although the change is welcome, it is often when horticulture problems arise in the past year. A typical example – Browning Evergreens. Extension educators and employees across the state have received reports of various types of evergreens with brown tips, dying and possible fungal infections. As early as 2025, plants with symptoms of winter injuries were Arborvitae, Cypress, Holly, Rhododendron, Boxwood, Pachysandra and Mahonia.

For many of these plantings, the problem may have started last summer and autumn when a large part of Pennsylvania was in a drought. Trees and shrubs that have been planted in the past 1-3 years are more susceptible to drought as established trees and shrubs. In addition, stressed drought plants are more susceptible to winter injuries and other stress factors such as fungal infections and increased insect printing. Evergreen plants that exacerbate the drought conditions from the last summers and the youngest cold winter are susceptible to drying out the tanning and death of plant tissue. Leaves and needles lose water in winter, especially when they are in places with a lot of wind or sun. The plants cannot replace the water when the soil is frozen in winter so that the leaves or needles dry out and become brown. Broadleaf -Evergreens such as Rhododendron may have rolled up leaves or outer blade.

Reducing the load on the plants is one of the best management options. Plants in protected areas and irrigation in longer dry periods can help reduce stress. Deep water supply is better than frequent, flat water decays. For plants that are younger under 5 years, you should consider watering down late autumn – before the floor is frozen – so that the plants have enough water in the winter. A 3-4-inch mulch layer helps to save moisture and isolate the soil.

In the case of wind protection systems, use species that are suitable for strong wind ranges. Some hybrid evergreens like Leyland Cypress are flat and quickly grow and do not have the longevity that offers other species.

If plant tips or limbs are brown, do not recover. Check whether the branches are still alive by scraping a small area with bark to look for a healthy green tissue. Dead plants should be removed. Cutting and removing completely dead branches on wooden plants that show to die. Cutting helps to stimulate new growth, reduces the areas for mushrooms to remove and eliminate inoculum if there is already an infection. The evergreen bundkobe, Pachysandra, is more susceptible to the disease if plants are stressed due to drought and winter injury. Thinging beds to improve air circulation reduces the disease.

Funizids can be used, but they only protect new growth. Examples of active ingredients for fungicide are copper, chlorothalonil and mancozeb. Read the label and apply according to the instructions.