The end of the growing season does not have to signal the end of tropical container plants that have brought months of enjoyment. “With a bit of care they can be carried through the winter and put to work the follow spring as outdoor patio plants,” said University of Missouri Extension horticulturist David Trinklein.
Tropical container plants represent a more sizable investment in plant material than do annuals, Trinklein said. “By overwintering, that investment can be amortized over several seasons of enjoyment.”
Many tropical plants suffer from chill injury when night temperatures consistently fall below 45 degrees Fahrenheit. Move them inside for protection.
It is possible to keep tropical patio plants active and growing indoors throughout the winter. However, it takes time and an indoor space with adequate light and suitable temperatures.
Place smaller plants in a sunny window. They should bloom periodically throughout the winter. Use other techniques if you have larger plants or lack adequate lighting indoors.
Put woody tropical container plants in a cool location and allow their leaves to drop. An unheated garage that maintains a temperature of 45-50 degrees will allow the plant to go dormant for the winter.
Dormant plants have no leaves and do not require much water, Trinklein said. Keep the root system “barely moist” during dormancy, but don’t let the roots dry out.
Hibiscus and bougainvillea are good examples of species to overwinter by forcing them into dormancy. Both will initiate new leaves and growth when placed outdoors after the danger of frost has passed the following spring.
Regardless of the species, thoroughly inspect plants for pests before moving them indoors, said Trinklein. Mites, a common plant pest, are hard to detect because of their small size. Eliminate mites by washing leaves thoroughly with a mild detergent or spray the plant with an appropriate pesticide labeled for use on mites indoors.
Other tropical plants can be overwintered by harvesting and safely storing the bulbs, tubers or corms they produce. Elephant ear is a good example. Its large leaves make it impractical to overwinter as a mature plant. Instead, dig its tuber after the first frost. Cure it for several days and put it in a moistened material such as peat moss. Store at temperatures in the range of 45-50 degrees.
“From the standpoint of overwintering, the 500-pound gorilla in the room has got to be banana,” said Trinklein. “What do you do with a plant that has grown to a height of six to eight feet in one summer?” The answer is simple, Trinklein said. Cut it back. Move the “stump” into an area where the temperature averages 45 to 50 degrees. Move it outside in spring after the danger of frost is gone.
In most cases, overwintering tropical plants not only saves money, but also results in larger, more impressive plants the next year, Trinklein said.