We grow a lot of tropical plants in our Houston-area gardens. Our heat and humidity has lulled many of us into perhaps a false sense of security: and with one hard freeze, we lose a lot of landscaping.
Here's a quick rundown on what's probably alive, and what probably isn't coming back.
Q: My elephant ears were covered during the deep freeze, but that didn't help. Is there anything I can do to save them. They are 25 years old. -- J.T., Houston
A: I know they look awful. But I imagine they will send up new shoots from the big bulbs in spring. Remove the soggy foliage now. Mulch. These are tough plants.
Q: The elephant ears have been frozen, and I have trimmed them back. Should I dig them up and store them in a cool place? — D.P., Conroe
A: If you have the commonly seen, old-fashioned elephant ears, Colocasia esculenta, there's no need to lift the bulbs.
They are so tough they've become invasive in many areas. If you're concerned, mulch will help protect the bulbs. Some more exotic species known as elephant ears are less hardy. To find out more, check our plant database at chron.com/plants.
Q: What is the fate of our palm trees that are brown from the freezes we've had? - A.M.V., Kingwood
A: It's difficult to say. A lot rides on how cold-hardy the variety is, the age and health of the palms, and how protected they are in your landscape. You may not know how extensive the damage is until warmer weather.
Palms can really suffer in a wet freeze. Horticultural Consultants, a wholesale/partial retail nursery at 5321-B Westpark, recommends spraying the foliage with an anti-transpirant and wrapping the trunk with Fiberglas insulation backed with foil to protect palms during freezing weather. The foil side should face out. An application of liquid potassium a week or so before a freeze will enable a palm to withstand cold three to six degrees lower than it normally would, a consultant says.
Do not prune your palms in winter.
Q: The fronds on my 4-foot date palm turned brown after the freeze. The trunk and roots seem fine, but will new fronds grow? -- M.W., Houston
A: If the trunk and roots are OK, there should be recovery, but it might be slow. It depends on how warm/wet spring is. The folks at Enchanted Gardens and Enchanted Forest nurseries say it's best to leave fronds with any green on the plant. This allows a bit of photosynthesis to help the tree. The nursery recommends removing other cold-damaged leaves, then spraying palms that don't bear edible fruit with a copper-based fungicide. Follow package instructions.
Here are the Lone Star Chapter of the American Hibiscus Society's suggestions to help your tropical hibiscus recover from winter damage:
Prune (after freeze danger has passed)
Cut the plant back to live, green wood. Don't be surprised if, after several weeks, the hibiscus needs more pruning. Freeze damage doesn't all show up at once.
If the plant has survived winter, new growth will emerge below the frozen parts when night temperatures are above 50 degrees.
This elixir will jump-start your hibiscus in spring: Dissolve 1 tablespoon each of a balanced water-soluble fertilizer (Peter's 20-20-20), Epsom salts and KNO3 (potassium nitrate) in 1 gallon water. Do not use more than 1 tablespoon of KNO3 or you could burn your plants. Apply again in fall.
For good growth through the season, apply a granular or water-soluble hibiscus food every two weeks in the spring, summer and fall. For extra benefits, foliar feed with a water-soluble fertilizer such as Space City (18-10-28) or Peter's.
Apply Epsom salts at a rate of 1 tablespoon per gallon of pot size, or throw a healthy handful around grounded plants once a month.
Epsom salts can be added to the water-soluble fertilizer and used as a soil drench or a foliar spray.
Tropical hibiscus blooms on new growth, so a freeze-damaged plant will need 90 to 120 days to put on enough new wood to begin blooming again.
Q: My oleanders were badly damaged by the latest freezing temperatures, and I would like to prune them to get rid of the ugly brown leaves. How do I know where to cut? Some branches have some green on the top as if new growth had occurred, others have a mix of mostly brown and some green leaves. How low do I cut them? - YBF, The Woodlands
A: Prune the oleanders back as far as you find freeze damage along the stems/branches. Healthy stems will be firm and green. This may mean you cut damaged branches to the ground. The shrubs will regrow from the roots, but for a while, of course, you will have a bare spot in the landscape if all branches are dead/damaged.
Otherwise, prune oleanders after blooming. Some varieties flower only in spring, but others are free-bloomers and flower through the summer. All types should be pruned by the end of August or early September to give any new growth sufficient time to harden off before winter.
Oleanders have a globular shape - a billowy, full form to ground level. Little pruning is required to maintain this natural shape. Broken, weak, crossing or dead branches should be removed. Unwanted stems can be removed at ground level or where they join older stems.
When there is no freeze damage, a rule of thumb is not to prune more than a third of the existing foliage and to prune stems carefully to distribute removal evenly for a balanced look.
Q: The tops of my gingers have frozen and are brown. Should I cut and remove them now or wait until the threat of freeze is gone? - T. B., Friendswood
A: You can cut them now or any time before new growth starts.
Q. The philodendron and cyperus were damaged. Do I cut these plants to ground level?- YBF, The Woodlands
A. Cut them to the ground - these will put on new growth soon.
Q: I didn't cover my bougainvilleas during the freeze. Should I prune them back now or wait until the threat of freezing temperatures is past? - L.W., Tomball
A: I like to wait to prune, since it usually means I start the growing season with a larger plant. Freeze-damaged wood provides some protection for live wood farther down the stems. If you don't care about this, you can prune now; but mulch well to protect the roots.
Q: I left several plumerias in the garden with freeze-damaged, black tips. Should I trim just the tips or cut off the entire branch? Will the branches or tips grow if I plant them? - H.M.B., Rosharon
A: You can remove an entire branch if you like, but it's only necessary to remove the freeze-damaged tips. Cut back to firm, white wood. You can root cuttings with healthy wood.
Q: I covered two Clerodendrum quadriloculare during the cold weather, but both look bad. What are the chances they'll recover from this damage? -- D.N., Houston
A: This species is listed as cold-hardy to zone 8; we're in zone 9 with minimum temperatures in the 20-to-30-degree range. Covering helped, possibly keeping temperatures 2 to 3 degrees warmer, and if the plants were mulched, chances are they'll return from the roots when warm weather returns. If you find firm, green wood closer to the base of the plant, you'll know sooner rather than later you're in luck.
Q: Will freeze-damaged ixora recover? -- K.H., Houston
A: Ixora's hardiness rating is zone 9b with minimum temperatures in the 25-to-30-degree range, so the plants could possibly make it. If you find firm areas, they could pull through. If plants are all mush, you'll need to see if anything comes back from the roots in spring. Meanwhile, keep living plants mulched and water before the next freeze, if it hasn't rained.
Source: Houston Chronicle archives, Garden Editor Kathy Huber.