Unfortunately, you can’t predict when frost will occur. It could strike before leaf buds emerge, or even after flowers blossom.
Because plants break dormancy by late spring, a frost at that time could cause more damage to trees and shrubs than an early spring frost.
When the temperature dips particularly low, a tree’s cambium tissue—the layer beneath the bark, where growth occurs—may suffer and cause more significant damage to the specimen overall. If the tree is otherwise healthy the wound should seal itself, but if not the wound can worsen and even be entry points for diseases and pests. During dormancy plant tissues are not susceptible to damages from freezing events. However, once dormancy breaks emerging tissues can become burned from lower temperatures.
Although frost may also prevent some leaves from expanding completely, it may cause other leaves to emerge with holes or distortions. Ornamental trees’ leaf buds are particularly susceptible to frost damage. Loss of flower buds for a season is not as crucial on ornamentals compared to fruit trees.
If your area experiences a hard frost in late spring, don’t attempt to remedy the situation for at least two weeks. Some plants are indeterminate growers, meaning they produce a second flush of leaves after the first. Most times these types of trees will grow out of frost damage.
Drought-stressed plants often lack the ability to withstand frost damage, so keep your trees and shrubs well-watered during the growing season, especially evergreens in late fall, to prevent damage in future seasons. You can help prevent frost damage. Most importantly, research your USDA Plant Hardiness Zone and the trees most compatible with your region’s climate conditions before planting new trees. This will help ensure your trees can withstand the weather patterns you may expect to experience throughout the year. For example, it’s not likely a Japanese maple tree can withstand the winter season of northern U.S. regions.