Newsarticle by

Bobby Fletcher

LSU AgCenter

We have encountered several freezing weather events in the last few weeks so it is important to know the correct measures to take in your landscape regarding removing dead foliage as well as other plant parts after freeze events. This research-based information will help you be a better gardener as well as help your plants recover from these cold weather events.

According to LSU AgCenter Horticulturalist Dan Gill, if gardeners used only plants that are hardy in our area, we would never have to cover them or be worried about them when it freezes. Gardeners trying to minimize maintenance, and those who consider covering and uncovering plants a major hassle, certainly should consider reducing or eliminating tropicals in their landscapes.

For those who love tropical plants, they are worth the extra effort it takes to get them through the winter. 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 to protect them – as well as the sad, brown foliage that results from winter freezes.

Tender perennial bedding plants are another group that are severely damaged or killed by winter freezes. These include impatiens, wax begonias, pentas, blue daze, scaevola, periwinkle and coleus. These plants can survive relatively mild winters. In South Louisiana, it is not uncommon for wax begonias and pentas to survive, especially in a protected situation. Although it’s nice when they make it through the winter and provide another year of flowers in our landscapes, we must remember these plants are not intended to be permanent.

Check for signs of life at the base of these plants after a freeze. 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, 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 hardy, cool-season bedding plants such as pansies, dianthus, alyssum, snapdragons, petunias or many others anytime from now through February for an outstanding display this spring.

Here’s some general information on what to do after a freeze is over:

·        If you moved container plants into a protected location in a garage or indoors, move them 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 on plants 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. You may leave plants covered with blankets or sheets for several days without harming them, but eventually the cover will need to be removed 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. Damaged growth on herbaceous or non-woody plants, such as cannas, elephant ears, birds-of-paradise, begonias, impatiens, philodendron and gingers, may be pruned away until you get back to living tissue. This pruning is optional, however, and is done more to neaten things up than to benefit the plants. On the other hand, if the damaged tissue is oozy, mushy, slimy and foul smelling, then it should be removed. Make sure the base of these plants is mulched at least 6-inches to 8-inches deep to protect the crowns, rhizomes, bulbs and roots. This will help ensure their survival.

·        You may remove the damaged foliage from banana trees, but do not cut back the trunk unless you can tell it has been killed. If that’s the case, it will look brown, feel mushy, be loose in the soil and will bleed a lot if punctured. The exception on not cutting back the trunk would be any banana trees that produced a bunch of bananas last year. They will not send up any more new growth from those trunks, and should be cut to the ground to make room for new shoots that will grow this coming 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. These plants are not as common in northern Louisiana, but I have talked to gardeners growing hibiscus and angel trumpets in northwestern Louisiana about cold protection.

·        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.

·        Finally, remember we may see additional freezes before it’s all over. Protect what you can when protection is needed. Don’t be too quick to dig up and remove tropical plants that have been severely damaged and appear to be dead. They may eventually sprout again from the base of the plant or the roots in April or May.

Question of the Week: When should I remove the fruit from my citrus trees and when is the best time to prune and fertilize them?

Answer: You need to remove the fruit from your trees by the end of January so they will bloom properly later this spring. February is the time to do any pruning on your trees as well as the time to fertilize fruit trees in our area. You need to get a copy of the “Louisiana Home Citrus Production Guide” from any Extension Service office as this is an excellent resource to have for future use. You can also get a copy from www.lsuagcenter.com.