Managing Winter Dormancy for Your Tropical Plants
Some tropical plants do best with—or may even require—a winter rest. How you care for these plants over the winter depends on the kind of space you have available, and whether the plants are soft-stemmed, woody, or bulb-like. Tropical plants that grow from bulbs or tubers, such as elephant ears, caladium, sweet potato vine and canna lily, should get nipped by frost before they're brought indoors. This sends the plant a clear message that the end of the season has come. At this point you can do one of two things. You can leave the plants right in their pots over the winter, keeping the soil barely moist, and store the whole pot in a cool, dark place. Or, you can trim off the stems, dig up the bulbs, label them, wrap individually in slightly moistened newspaper or peat moss, place them in a black plastic garbage bag and store a cool, dark place. In either case, it is important that air temperatures remain at about 40 to 50 degrees F. Check the bulbs monthly to make sure they are still firm and solid. If they are drying out, mist the storage material around them with a little water. When spring arrives, repot the bulbs, begin fertilizing regularly, and put the plant in a sunny window.
Woody-stemmed tropicals, such as jasmine, brugmansia, tibouchina and bananas, should be brought indoors before the first frost. Let the plants rest in a cool place (40 to 50 degrees F) with little or no light—they'll get the message that winter has arrived and their leaves will gradually yellow and drop. The plants can then spend the winter in an unheated basement, root cellar, unheated garage, or even a cool closet. Make sure the area is relatively dark (try enclosing the whole pot loosely inside a heavy black trash bag) and that the air temperature stays above freezing. In most cases, woody-stemmed tropicals should not be cut back until early spring (unless you can't fit them into the house!). Water the plants sparingly throughout the winter, checking monthly to see that the soil is barely moist. When early spring arrives, revive the plants by repotting them in fresh soil. Water thoroughly and provide a weak dose of liquid fertilizer. Expose the plants to bright, filtered light, gradually acclimating them to full sun. Try to give them about a month of indoor (or greenhouse) growing time before moving them outdoors.
When it comes to reintroducing heat-loving tropicals to the outdoors, always do it slowly. Shield them from direct sunlight and wind for at least a week or two. If the plants are acclimated slowly, they'll slide right into active growth. Too much early spring stress will stunt the plant's growth—or even kill it.
The truth is, overwintering tropical plants involves a bit of trial and error. A technique that works well for one type of plant or in one particular winter environment may not be ideal for another. Be prepared to lose a few plants.
Overwintering Techniques
- Overwinter as houseplants: cordyline, phormium, palms, croton, bamboo, jasmine, allamanda, bougainvillea, hibiscus, citrus
- Keep plant dormant in a cool, dark place: brugmansia, banana, dwarf canna
- Store dormant bulbs/corms/tubers: begonia, dahlia, ginger, sweet potato vine, colocasia, caladium, canna, calla
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