Unseasonably warm temperatures across Iowa this February have triggered early bud development on red maples and red maple hybrids. Many trees are beginning to leaf out weeks ahead of typical leaf emergence, and colder weather is expected this weekend.
A return to freezing or near-freezing temperatures can injure newly emerging leaves that are not yet hardened. This type of cold damage is fairly common during early warm spells followed by late winter cold snaps. “In many cases, the damage is not immediately obvious,” said Tivon Feeley, forest health program leader with the Iowa Department of Natural Resources. “Symptoms often appear later in spring or early summer when affected portions of the leaf tissue dry out and fall away, leaving holes or irregular edges in the leaves.”
This condition is sometimes mistaken for insect feeding or disease, but it is simply a delayed response to cold injury that occurred earlier in the season. Although the damage may affect the appearance of the tree for a short time, it is not fatal and does not pose a long-term threat to tree health.
“Early leaf damage caused by late winter cold snaps are cosmetic and temporary,” he said. “Trees affected this spring will recover on their own as weather conditions stabilize.”
Homeowners are encouraged to monitor their trees, but there should not be a need for extra pruning, fertilization, or pesticides.