Earlier this week, we again experienced a hard freeze. And remember the early freeze that much of our area experienced during mid November. This was followed by a warming trend with, at times, unseasonably warm weather during the latter part of November through most of December. This “rollercoaster” ride of temperatures typically continues throughout our winters in North Florida.
As a result of freezing periods, the less cold hardy woody landscape plants can be injured. For example, it’s normal for landscape plants such as oleander, hibiscus and bottlebrush to suffer some cold damage. Then, the first impulse for many gardeners is to cut away the dead and dying leaves and branches. But this is not the best idea.
Delay pruning and fertilization of cold injured plants until new growth occurs in spring. Pruning and fertilizing can force plants to produce new growth, particularly during the upswing of temperatures during our winters. The resulting new, tender growth will be more susceptible to the next freeze/frost. When new growth occurs in spring, you’ll know what survived and what didn’t. That’s the time to prune and/or fertilize.
Some of the more tropical landscape plants such as banana, cassia, ginger and many of the tropical perennials may be killed back to the ground. Don’t give up on them too soon. Some of these plants require warm soil temperatures before they’ll produce new growth. They may not show any signs of life until April or May.
Be prepared to cover the more cold sensitive landscape plants. But remember that covering a plant without additional heat is primarily a method of protecting against frosts rather than freezes. Drape the covering to the ground to trap heat under the covering. It’s best to use cloth rather than plastic. Heat from an ordinary light bulb placed under the covering will provide additional cold protection.
Leave cloth-type covers such as sheets and blankets over plants as long as temperatures are dropping to freezing at night and are rising to no more than the 50s during the day. But remove plastic covers when temperatures rise above freezing. Remove all covers when night temperatures are consistently above freezing. Leaving plants covered day after day may cause them to break dormancy under the warm covering. They will then be more susceptible to cold injury during the next freeze.
Cold weather will come and go throughout our North Florida winters. Be prepared to protect your prized plants each time freezing weather is predicted. Resist the urge to prune and fertilize too soon. As spring approaches, you’ll have a better idea of what survived and what did not.
Larry Williams, UF/IFAS Extension Agent, Okaloosa County, January 8, 2015