Garden Success Tip of the Week
Overwintering Tropical (and non-hardy) Plants – Tropical plants make a wonderful addition to the deck, patio and even the landscape during the summer season. In general, these are heat loving plants and will perform (and flower in many cases) quite nicely during the hot summers. But once fall arrives, what do you do with these cold sensitive plants? You could kiss them goodbye and let the fall frosts kill them off. But many gardeners would like to give them a shot keeping them alive indoors over the winter. And to be honest, this takes space indoors, your time and patience, and a bit of trial and error (prepare to possibly lose a few plants). What works for one may not work for another. Your indoor conditions may not be conducive for overwintering tropical plants. Nevertheless, if you want to give it a try, here are a few tips for you. Good luck!
Overwintering Options – You have a few choices when overwintering tropical or non-hardy plants. –Bring inside and grow as a houseplant -Store it away as a dormant plant, tuber or root -Collect seed and start again next year -Take cuttings and grow those indoors over the winter -Leave outside in protected area with suitable added protection
Overwintering as a Houseplant – Be sure to follow the procedures listed in our tip sheet on bringing plants indoors for the winter. Once inside, most houseplants need two major requirements – high amounts of light and added humidity. As a general rule, only water as needed, and watch for sudden outbursts of insect problems. And do expect some leaf drop as they adjust to the indoors environment. Foliage plants, jasmine, bougainvillea, hibiscus, citrus, gardenia, Mandeville, annuals, elephant ears (alocasia / colocasia); even bananas can be overwintered as a houseplant. And if too large to fit, feel free to cut them back as needed, but making sure to leave some foliage on the plant.
Overwintering Dormant Plants / Tubers – Many non hardy plants are grown from tubers, corms or roots which are dug up in the fall, generally after the first frost, stored indoors over the winter, then replanted next spring. Elephant ears (alocasia / colocasia), caladium, cannas, gladiolas, dahlias, sweet potato vine, agapanthus, etc are examples of this. These are dug, cleaned, and stored in peat, newspaper, etc in a cool dark place (40-50 degrees). Check them regularly for dryness or rotting. These can also be stored away in the same manner if growing in pots. Simply remove old foliage and store pot and all in a cool, dark place. Some plants can be stored over winter in the same basic manner, simply by bringing them indoors before the first frost and placing them in a cool (40-50 degrees) place with little or no light. They will lose their leaves and go into a dormant stage for the winter. Water once per month (lightly) to keep slight moisture in the soil. In the spring, cut the plants back, bring them back into a well lighted area (nothing direct for the first 2 weeks or so) which will wake them from their winter sleep. Plants that can be stored indoors in a dormant stage include bananas, ensete, hibiscus, Angel trumpet, tibouchina, jasmine, etc.
Overwintering Cuttings – Many annuals perform quite nicely over the winter (indoors) by taking cuttings from the parent plant and overwintering the cuttings. 3-4 inch pots usually work best, and can be kept on a windowsill. Many folks like to overwinter geraniums, and although is best done with cuttings, can also be done growing as a houseplant, or by digging and bare rooting the mature plants before the first frost, and placing them in a paper bag in a cool dark place (40 – 50 degrees). They will go dormant. Mist lightly every now and then. In the spring, bring them out of the bag, cut them back, replant in a pot, and see if they regrow. (This was the way Grandma used to overwinter her geraniums, except she hung them upside-down in the cellar rafters.)
Overwintering Outdoors – If you have a banana that you would like to try and overwinter outdoors, here are 2 methods to try. 1.) After the plant has been hit by a good frost, cut the top back to one foot below the leaf axis. Surround the stalk with a chicken wire cage that is 2-3 feet in diameter. Fill the wire column with leaves, straw, grass clippings, bark mulch, etc. Then cover the entire structure with heavy plastic or tarp and secure with twine. 2.) Follow above procedures, but rather than using chicken wire, simply invest in bubble wrap. Make 5 to 10 laps around the cut banana stalk with the bubble wrap, and then cover over the top opening to protect from rain and snow. Tie it all together with heavy twine. If you’d like, feel free to add 5-6 inches of mulch around the base for added root protection. For those in Zone 5 or lower, you may have best success taking the banana indoors for the winter (bare root and store in cool dark place).
Again, successful overwintering of non hardy / tropical plants will take trial and error, and not always be successful. But, if you are, then it was worth the effort come next summer!