The hard freezes of this past week have damaged our tropical plants. Gardeners trying to minimize maintenance — and those who consider covering and uncovering plants a major hassle — should consider reducing or even eliminating tropicals in their landscapes.
But for the rest of us, tropical plants are worth the extra effort. Their ability to thrive during the intense heat and humidity of summer and the beauty of their foliage and flowers ensure that many gardeners will put up with the effort needed to protect them in winter and the sad, brown foliage that results from freezes.
Despite its effect on tender tropicals, this week’s almost record cold has not been enough to damage hardier plants, such as azaleas and gardenias. This sometimes happens when temperatures plunge to the low teens. But on the north shore, temperatures in the 30s and upper this winter have not damaged hardy trees, shrubs, ground covers and lawns.
Also, many damaged tropicals will recover, especially if given protection. In North Carolina, temperatures stayed in the 30s. While the damage is extensive, if we don’t get anything worse, our landscapes should recover.
Despite how terrible this damage looks, it may be a benefit in disguise. With their exuberant growth, some tropicals seem determined to take over our yards. Few gardeners have the heart to prune back the plants to keep them under control because they bloom so frequently, and no one generally wants to cut back a plant in bloom. Now, nature has dealt with the situation for us by freezing back overgrown tropicals, and in many instances, we and our landscapes will be better off for it.
Another group of plants that has been severely damaged or killed are tender perennial summer bedding plants, such as impatiens, wax begonias, pentas, blue daze, scaevola, periwinkle and coleus. Although it’s nice when they make it through the winter and provide another year of flowers, we must remember these plants are not intended to be permanent. Check for signs of life at the base of these plants. If you still see some green, cut the plants back to the living parts and don’t forget to mulch over or cover them should we have additional freezes.
If yours have been killed by sub-freezing temperatures (more likely on the north shore), remove the dead plants from the bed and mulch over the area to keep it looking neat. You also could prepare the bed and plant cool-season bedding plants, such as pansies, dianthus, alyssum, snapdragons, petunias or many others, anytime now through February for an outstanding display this spring.
The worst of the recent freezes will be over by this weekend, and you can begin to assess the damage.
Here are some general tips on what to do after the freeze:
- Move container plants back to their location outside unless you intend to keep them inside for the rest of the winter. If you will keep them inside, make sure they are close to windows and receive plenty of light.
- For plants that you covered, remove or vent clear plastic covers to prevent excessive heat buildup if the next day is sunny and mild. You do not need to completely remove the cover if it will freeze again the next night. We have left our plants covered all week as freezes occurred night after night, but this weekend it is time to uncover them so they can get light.
- Do not prune anything for several days after a freeze. It often takes several days for all of the damage to be evident. You may even find that some plants that look damaged immediately after a freeze actually aren’t. I left a pot of Easter lilies in active growth out to see if the cold would hurt them. (It got down to 19 degrees in my area.) After the freeze, the foliage looked dark and water soaked, and I was afraid they had frozen back. By the next day, though, the foliage was bright green and healthy.
- Damaged growth on herbaceous or non-woody plants, such as cannas, elephant ears, birds-of-paradise, begonias, impatiens, philodendrons and gingers, may be pruned back to living tissue. This pruning is optional, and is done more to neaten things up than to benefit the plants. However, if the damaged tissue is oozy, mushy, slimy and foul smelling, it should be removed.
- Remove the damaged foliage from banana trees but do not cut back the trunk unless you can tell for sure that it has been killed. It will look brown, feel mushy, feel loose in the soil and will bleed a lot if punctured. The exception would be any banana trees that produced a bunch of fruit last year. They will not send up any more new growth, and should be cut to the ground to make room for new shoots that will come up this summer.
- Dead leaves on woody tropical plants, such as hibiscus, tibouchina, angel trumpet, croton, ixora, schefflera, copper plant and rubber tree, can be picked off to make things look neater. If you can clearly determine what branches are dead on a woody plant, you can prune them back.
- Try scratching the bark with your thumbnail. If the tissue underneath is green, it’s still alive. If the tissue is tan or brown, the branch is dead. Start at the top and work your way down to see how far back the plant was killed. Generally, it’s a good idea to delay hard pruning of woody plants until new growth begins in the spring and you can more accurately determine which parts are alive and what is dead.
Remember, we may see additional freezes before it’s all over. Continue to protect what you can when needed. And, don’t be too quick to dig up tropical plants that have been severely damaged. They may eventually resprout from the base of the plant or the roots in April or May.