If you have young trees or shrubs, now is time to protect them from Sunscald Injury. This occurs in winter when the southwest exposed trunk of a young tree is exposed to wide temperature swings. The bark of many young trees is very thin and the living layer of bark, the phloem, is killed by the repeated freezing at night at the heating up during the day. The damage weakens the tree and is unsightly. At the tree ages, the bark thickens and is less susceptible to the winter temperature swings. There are several ways to protect the tree trunk by reducing the excessive heating from the sun during the day. The trunk and large branches with southwest exposure can be wrapped with white flexible tape or plastic tube wrap. The wrap or tube needs to be removed in the spring after the last frost and reapplied in the fall. You can also paint the trunk with white, indoor latex paint (outdoor has additives that are harmful to trees). It can be diluted with 1:1 with water and leaves the trunk white which may not be pleasing to the eye. I did not receive any instructions about sunscald and as a result have a very disfigured tree. I’ve enclosed a picture of a Golden Raintree (Koelreuteria paniculate) I bought at an Albuquerque nursery over 10 years ago.
Edith Iwan is a Cibola- McKinley County Master Gardener who lives and works in Thoreau. As a Master Gardener she assists the County Cooperative Extension Service in providing accurate, research-based gardening information to county residents. If you have any gardening questions, please call the NMSU Cibola County Extension at 505-287-9266 or NMSU McKinley County Extension at 505-863-3432.