Kathy Zuzek, Extension Educator
If you are seeing damaged leaves on shrubs and trees, it may be due to the below-freezing
temperatures that occurred throughout Minnesota between May 14 and 18. Nighttime temperatures around much of the state dropped into the 20’s and the succulent newly-emerged leaves of some trees and shrubs froze. Frost damage first appears as water-soaked wilted tissue that later turns brown or black as it shrivels, curls, and dies. Entire leaf kill results in eventual leaf drop. Partially injured leaves may remain on plants as misshapen leaves.
Healthy trees and shrubs will not be greatly impacted by frost damage because they use stored energy reserves to produce new replacement leaves. When frost damage occurs, trees and shrubs initiate a stress response that 1) stimulates dormant buds near damaged leaves to expand into new leaves and/or 2) stimulates production of new adventitious buds that will develop into new foliage to replace damaged leaves.
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| Frost damage on oak leaves. Photo: K. Zuzek |
Healthy trees and shrubs will not be greatly impacted by frost damage because they use stored energy reserves to produce new replacement leaves. When frost damage occurs, trees and shrubs initiate a stress response that 1) stimulates dormant buds near damaged leaves to expand into new leaves and/or 2) stimulates production of new adventitious buds that will develop into new foliage to replace damaged leaves.
