No doubt it has been a strange winter season. We have had a mild winter followed with winter weather this week. Changes in the weather like this can leave plants and gardeners confused and frustrated. The early warm weather can cause many plants to flower and leaf out much earlier leaving young, tender growth vulnerable to cold damage.
So what does a late cold spell mean for the health of your plants? Plants that were already flowering and putting on new growth before a cold spell are the ones most susceptible and where we could see some damage. Fruiting plants that were flowering, such as blueberries, fruit trees and strawberries, can see damage and could have reduced fruiting. However, to see significant reduction in fruiting on these plants would take several days of freezing weather, not just a drop in temperatures over one night.
So, the big question is what do gardeners do for plants if we see cold damage? It will usually take a few weeks to see damage from cold temperatures. It is best to wait, give the plants time to recover before assessing the damage. Even though you may see damage early, do not prune anything for a few weeks. It will take some time for any damage to be apparent. After a few weeks, damaged or dead growth can be removed. Pruning is optional and will not help the plant deal with damage. It is generally better to delay hard pruning of trees and shrubs until new growth begins so you can more accurately determine which parts survived. If you do prune, make sure branches are dead before removing. You can determine if branches are dead by scratching the bark with your thumbnail. If tissue underneath is green, it’s still alive. If plant tissue is tan or brown, the plant material is dead. When pruning damaged branches, start at the top and work your way down to see how far back plant was killed. Don’t be too quick to give up or get discouraged with cold damaged plants. Even with plant material that was frozen, many will recover by putting out new growth in the spring and summer. It may take longer for new growth to emerge as it takes time for the plant to recover.
For fruiting plants, such as blueberries, strawberries and fruit trees, it can be a wait and see game to determine fruit loss. It will depend on how cold and how long the plants stay cold as to if any cold damage occurs. Many fruiting plants see damage when temperatures are at 30 to upper 20’s. However, blueberries and strawberries do not open all their blossoms at once, so you may lose some flowers (and potential fruit) but more flowers could open in coming weeks. Fruit trees see a very limited crop when temperatures dip down to 25 degrees. Temperatures in upper 20s cause some blossom loss and could actually be helpful to trees that set many more fruits than they can support, by naturally thinning the fruit.
If you get excited with early warm weather and plant summer annual vegetables (such as tomatoes and peppers) and flowers outside too early, they may not survive a cold snap without any protection. If these types of plants were not protected, they will need to be removed and replanted. Wait to plant these summer vegetables and flowers until at least after April 15th, which is the average last spring frost date.
Having a late spring freeze or early warm temperatures in late winter does occur on occasion in Eastern North Carolina. We often wait until the last minute and scrabble to find ways to protect our plants. Instead, start now in preparing and storing what you would need to protect plants for future late freeze events. Row covers or cold protection covers can be found through gardening supply companies online and in our area. Having this on-hand will provide protection from cold damage in the future.
Jessica Strickland is an agriculture extension agent specializing in horticulture for the North Carolina Cooperative Extension in Wayne County.
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