Many of the tropical plants that we grow in Wisconsin as annuals can be overwintered indoors. If you are fortunate enough to have a large south-facing window you might be able to keep them actively growing throughout the winter.
Many can also be overwintered in a dormant state. Tropicals that grow from tubers or bulbs, such as Dahlia, Canna, Gladiola, Caladium, and Elephant Ear (Alocasia / Colocasia) are easily overwintered this way. I have even had success using this technique with tropical Banana (Musa / Ensete).
If planted in the ground:
- Dig bulb/tuber before hard frost.
- Cut the foliage off at the soil level.
- Place the bulb/tuber in a breathable paper bag. Do not use plastic as it will cause the bulb to rot.
- Include a small amount of dry peat moss or sawdust in the bag with the bulb/tuber.
- Place the bag in a cool, dry place (I use the basement).
- In spring replant the bulbs once the danger of freezing is past.
If grown in containers:
- Simply bring the entire container into a cool, dry place for winter storage.
- Cut foliage off at the soil level.
- Bring the container back outdoors once the danger of freezing is past.
Another technique for your tender plants
Our Merchandising Manager, Cheryl, has a large tropical Hibiscus that she has been bringing in and out for over 20 years. Since so much light is required to keep a Hibiscus actively growing all winter, she prefers to allow hers to go dormant. She places it on a large tarp in her basement (which has small ground-level windows) and waters it sparingly every 10-14 days. The plant will drop all or most of its leaves onto the tarp and remain dormant through the winter. In mid-May, once the danger of frost is past, she brings her plant back outdoors and begins watering and feeding it regularly. She prunes it very lightly, removing only branch tips that have died over winter. By mid-summer, she has a gorgeous, large Hibiscus, filled with blossoms!