An untimely frost event occurred last week that is showing its effects this week. Trees such as Dogwood, Japanese Maple, Sweetbay Magnolia, Holly, Tulip Poplar and many others, were just pushing new growth when the frost happened, leaving behind wilted, blackened foliage. Most trees and shrubs are capable of putting out a second set of leaves (but not flowers) during the rest of the growing season, but that activity stresses the resources of the plants. There are several things that can be done to care for these stressed plants…
DO:
• Make sure the plant does not suffer from drought for the remainder of the growing season. A rule of thumb is that it will need the equivalent of one inch of rainfall per week. Water it – once a week is probably fine – when we do not get that much rain.
• Mulch the plant with some form of woody mulch. This can be commercial mulch, sawdust, wood chips, or similar material. Mulches serve as blankets that protect both temperature and moisture in the root zone. Place mulch 2 or 3 inches deep around the plant, in a circle that extends out to the edge of its crown. Make sure to leave a “breathing space” right next to the bark – don’t pile mulch up against the stem/trunk of the plant.
• Wait a couple of weeks to a month to see how the plant will recuperate (mulching and water monitoring should be done right away). Prune off obviously dead material, and consider pruning to reduce the overall size of the crown of shrubs.
DON’T:
• Panic! Trees especially have seen a lot of abuse in their lifetimes and will weather this event, too. Help them out if possible, but don’t give up on their ability to regenerate.
• Add fertilizer to trees and shrubs at this time. Fertilizer tends to increase top growth on the plants, and the roots are already stressed to produce a new set of leaves with whatever reserves they still have. Adding fertilizer at this time would stress the roots further. You may add fertilizer this fall to help the plants through next winter.
It is hard to say at this point if damage will show up later. The cambium was very active on many trees and shrubs at the time of the freeze. This may lead to vertical cracks in the trunk in late May or early June. Unfortunately there is nothing that we could have done or can do at this point to prevent damage. Some of these trees will die as the weather becomes hot and dry. Wrapping the trunk, using duct tape, painting the wound, and nailing or using glue to keep the bark from peeling off any more is not going to help. Watch for opportunistic insects and diseases. This is especially true for various borers (i.e. dogwood borer, flat headed apple tree borer).
