Frost Cracking

Monday, December 7, 2015

During the winter we prepare for harsh weather by piling on layers of clothing and wearing heavy coats, gloves, hats and scarves; unfortunately, not many people think about how the living things in their yards and gardens react to the cold.  Trees and shrubs are vulnerable to cold weather just like we are. If new growth in the early Fall doesn’t have enough time to harden off, experts say the sudden drop in temperatures can create ice crystals that can rupture cell walls, resulting in dead branch tips and branches.

Officials at a state cooperative extension service say one of the biggest problems for trees and shrubs is the sharp temperature change from day into night during the winter.  They say that dramatic change can actually freeze the water in the trunks of trees, causing them to explode or split open. That reaction is called frost cracking. Sometimes these cracks can close when warm weather returns, if the damage isn’t that severe.  Many shrubs can suffer from something similar, called bark split. Extension service officials say those particularly susceptible are many cultivars of evergreen azaleas. In most cases plants close over the cracks with no treatment necessary.

During this winter there are some things you can do to protect your trees and shrubs.  You can wrap the trunks with burlap strips or commercial tree wrap. Experts also recommend painting the trunks white or shading them with a board to prevent bark splitting.  These methods reflect sunlight and reduce temperature fluctuations, like the buildup of heat during the day, that cause splitting. All wraps should be removed after one season to stop insect or moisture damage.