The Garden Guru: Make winter arrangements for sensitive plants

Posted Friday, Nov. 08, 2013  comments  Print Reprints

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This time of year, those of us in the plant-advice business are asked repeatedly about overwintering tender patio plants. We all hate to see plants die with the first freeze, yet there’s only so much space available to bring them indoors. So the question becomes, “Can I cover it to protect it?” And the second question that follows is, “Will it survive in my garage?” Let’s get those two inquiries out of the way, then we’ll look, plant by plant, at how best you can proceed.

If you’re talking about a truly tropical houseplant or patio container plant, there isn’t really a way you’re going to be able to cover it enough to pull it through a Metroplex winter. Just covering it with sheets, quilts or frost cloth may gain you a degree or two of protection, but that’s way off the mark. And building some kind of unattractive little plastic canopy over it probably will only frustrate you more — those things overheat almost instantly when morning sun hits them on those coldest, clearest days of mid-winter.

Second question: that garage thing. Again, I’m playing the part of the grouchy old guy for this one. Garages are almost always way too dark and way too cold for tender tropicals to survive a four- or five-month imprisonment. That’s even the case if you rig up artificial lighting. It still won’t amount to the light they need. Sad plants. Sadder gardener.

So we move to two plans that will work! Let this be the year that you invest in a small hobby greenhouse. (You’ll love it!) Or clear out a little space in your sunroom and bring your most prized tender plants in to spend the winter with you.

Those, then, are the generalities. Here are short-form suggestions for overwintering specific plants — the types about which people ask the most. There are a lot of them, so pardon that my answers will be both blunt and brief. But they’re also based on several decades of watching these plants and the gardeners who grow them locally.

Caladiums. Let them go. The trouble it takes to dig, dry, dust (sulfur) and store the dormant tubers over winter simply isn’t repaid by the poor results you get when you plant them the following April. I rarely hear from anyone who does this more than one time.

Tropical hibiscus. These plants must have sunshine in the winter, and they suffer chilling injury when it drops into the 40s each night. Give them full or nearly full sunlight at 65 or 70 degrees. It’s the greenhouse or sunroom for them.

Bougainvilleas. Again, you’re talking about a very tender tropical, and they must have bright sunshine and 70-degree temperatures or they’ll start dropping leaves. They must not be left outdoors in sub-freezing weather. These little babies need to come inside to the sunroom or into the warm greenhouse. They’ll pout in the garage — if they even survive.

Bananas. Aha! A lush tropical plant that will survive the winters outdoors! Let them die back to the ground the night of the first killing freeze. A day or two later, pull all the frozen stem stubble out of the way and apply a layer of shredded tree leaves as a mulch over their crowns. Left in place, they should sprout the following spring in our area. Those few years that they don’t: Hey, new plants are cheap.

Gold Star esperanza. This plant can handle light freezes (as in San Antonio, Houston and Corpus Christi), but here you need to figure out a way to get it into a greenhouse. They’re a bit too unruly to bring into the house. In fact, they’re inexpensive enough that you’ll probably decide to replace them.

Crotons. Everybody loves these showy foliage plants. And they love sunshine as much as we love them. You’ll want a greenhouse or an extremely bright south- or west-facing window. Grow them in too little light and all of their new growth will be spindly and green. The brighter the light, the better the colors.

Purple fountaingrass. With all the furor over ornamental grasses, people are surprised to hear that this one type is not perennial here. Unless it’s in an ultra-protected atrium (or in Brownsville), it won’t make it through the winter. Dig it and bring it inside? Oh, please. It’s a grass. Let the greenhouse growers get this one ready for your landscape next year.

Ornamental sweet potatoes. OK, I confess. Only a few people actually ask about bringing these pots indoors for the winter. (The plants get huge!) But scores of people ask about eating the large roots they discover when they start to rework their beds in the process of planting new pansies. Think of it: a sweet potato root the size of a bowling ball! The problem is that their texture and flavor are also comparable to those of bowling balls. Your dentist and your gastroenterologist join me in suggesting that you pass on this delicacy.

Neil Sperry publishes “Gardens” magazine and hosts “Texas Gardening” from 8 to 10 a.m. Sunday on WBAP AM/FM. Reach him during those hours at 800-288-9227.

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