By George Weigel/The Patriot-News
Q: We have a large hibiscus with pretty orange flowers and some red ornamental
grasses that do not survive the winter months outside here. I thought maybe if I put these in the cellar, they'll survive so I can regrow them next year.
A: You're on the right track. Most tropicals can be kept alive inside over winter, but next to a sunny window is usually better than in a basement - unless you've got a bright basement.
Your plants will get leggier than outside, but the idea is to keep the roots alive until next spring. You can always cut back the leggy growth in the spring and let the plant get a fresh start outside.
Tender plants like tropical hibiscus, peace lilies, orchids and such should come in before nighttime temperatures dip into the low 40s. That's late September most years. Hose down the plants or spray with insecticidal soap before bringing them in to head off bringing bugs in with the plants.
Over winter, the idea is not to push growth, just to maintain life. Don't overwater. That's the main way you'll kill your overwintering tropicals. Go with light-weight, high-quality, soilless potting mix in the pots. Use little, if any, fertilizer.
Bright light limits the legginess. So do cooler temperatures, which is why the basement would be great if you've got good light there. Placing your plants under a "grow light" (special lights that have spectrums to simulate sunlight) is another option - either in the basement or in any room in the house with lower light.
In low light, the tropicals may shut down altogether over winter. Even then, don't give up on them. Some may push up new growth again when more familiar light and growing conditions return. That may be what happens to your grass and to tender bulb plants such as elephant ears, caladium, colocasia and others. These appreciate a rest in winter.
Next spring, cut your overwintered tropicals back sharply before starting to acclimate the plant to the outside around mid-May. Start in a shady area for a couple of hours and then gradually increase the sun and time outside over a 7- to 10-day period. Then plant or set in their summer positions and resume fertilizing and other outdoor care.