by Kirsten Conrad, Extension Agent, Agriculture and Natural Resources & Environmental Horticulture
Photos by Kirsten Conrad
Though snowfall can transform our landscape in ways beautiful and wondrous, heavy snowfall can also cause astounding harm. Trees and shrubs broken under the weight of snow and ice need to have damaged wood carefully removed.
Expect to see damage on broadleaf and coniferous evergreens like magnolia, pine, cypress, hemlock, cedar, camellia, and rhododendron. Herbaceous plants and most trees will be fine, but homeowners are advised to carefully remove as much snow as possible from limbs and branches and then gently lift and shake them. Do not pull branches out from under heavy accumulations of snow. Multistemmed plants like Sky Pencil Holly or varieties of arborvitae can sometimes recover their form if their stems are tied together lightly and temporarily at two or three points. A vertical stake planted adjacent to a bent-over plant and tied gently to a woody plant leader may allow it time to straighten.
Broken branches should be pruned to remove jagged, torn limbs as soon as the snow has melted and damage can be assessed. Where branches have broken close to a trunk, use thinning cuts to remove broken limbs back to the branch collar at the trunk. Where only the branch ends have broken, limbs can be cut back to a side branch that is no smaller than one-third the diameter of the broken limb. The side branch will become the new leader. “Holes” that are opened in the canopy will spur new growth in response to increased light exposure and, in some cases, will fill with new growth within a couple of years.
Where branches have ripped away bark from the trunk of a tree, make a clean cut of the torn bark and broken branch, if possible, and see if the cambium layer will produce new growth to cover the wound. In severe cases, a new cut of the branch or trunk will be needed below the level of the damaged bark. Home landscape gardeners should exercise caution when pruning damaged trees and removing branches that may be hung up or still attached to the tree. Nonprofessionals should use power equipment such as chain saws only while standing on the ground.
Virginia Tech has resources on trees and shrubs, including pruning guides and calendars. No treatment of any kind is needed for helping trees recover from broken branches other than making clean cuts with sharp tools. Concerns about safety and stability of large trees should be directed to an International Society of Arboriculture certified arborist. This “Find an Arborist” tool has more information.
Virginia Cooperative Extension offers pruning classes, usually at the end of February, as well as classes about tree selection and disease. The Master Gardeners of Northern Virginia website offers resources on pruning and other subjects. For questions about pruning and other plant care, contact the Extension Master Gardener Help Desk at mgarlalex@gmail.com or 703 228 6414.