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Time to rescue tropical plants from chilly nighttime temperatures

Published: October 01, 2009

Story Source: Mary Kroening, 573-882-9633

COLUMBIA, Mo. - With overnight temperatures dipping toward the first frost mark, it's time to prepare tropical plants for the trek indoors, said a University of Missouri Extension horticulturist.

"If your space is limited, you will have to make decisions on which plants to overwinter and which to discard," said Mary Kroening.

Tropical plants need bright light to thrive indoors through the winter. If space and light are limited, it may be best to discard your annuals and buy new plants next year, she said.

Bring in succulent plants such as cactus and agaves before first frost. They can overwinter as houseplants with minimal watering.

Cannas and elephant ears are easy to overwinter. Dig them up after the first frost and cut back the tops. Store the rhizomes in peat, vermiculite or sand in a cool, dry location.

In spring, cut the rhizomes into pieces with several growing points each and start them as new rhizomes.

"I find it easier to move the pots indoors, give minimal care throughout the winter, and move the pots back outdoors during the spring," she said. "They easily go many weeks without water and can be cut back severely to reduce size when space is a limiting factor."

Banana plants overwinter wonderfully as houseplants, and they can be cut back completely when bringing indoors, she said.

Tuberous begonias and caladium also can overwinter with some success. If tuberous begonias are growing in containers, bring them in for winter enjoyment as houseplants.

Any houseplants such as fig trees, palm trees, Christmas cactus or hibiscus that you have placed outdoors for the summer need to go back inside before temperatures dip below 40 degrees.

"Whichever plants you bring indoors, carefully inspect them for insects that will proliferate in the warm, dry indoor conditions," she said.

If you find insects, spray the leaves thoroughly with an insecticidal soap or a pesticide approved for indoor use. Isolate outdoor plants from any indoor plants for about two weeks to ensure you don't contaminate your houseplants.