Living and gardening in a non-tropical zone doesn't stop gardeners from welcoming the tropics into their gardens. It's hard to resist those flashy beauties in the garden center each spring and even harder to say goodbye to them in the fall. Many people have succumbed to the imposing leaves of elephant ear (Colocasia) and the striking colors of cannas. Trumpet-flowered mandevilla grows nicely in a container and can cover a fence in never-ending color, at least until frost. Then there are banana trees, which will probably never produce bananas, but make quite the statement in the garden nevertheless. And who isn't charmed by angel's trumpet (Brugmansia) with its foot-long trumpet horn flowers that obligingly hang upside down so you can fully take in their heady scent.
These tropical plants add a touch of the exotic to our gardens, providing a taste of warmer climates for the duration of summer. But they don't come cheap and to grow a really impressive specimen takes years. Growing them as annual plants seems a waste of not just the resources put into buying and caring for the plants, but also the plants themselves. It is possible to keep your tropical treasures for more than a summer. However, if you want to enjoy your tropical plants for years to come, you will need to find somewhere safe to store them for the winter.
That safe place can vary from plant to plant. Some plants will happily go dormant in a sheltered spot, grateful to have the winter off and a little downtime to regain their stamina. Others make excellent indoor plants if you have a spot with enough sun and you can control the heat and humidity.
It's not easy making an outdoor plant happy indoors, especially in the winter. Days are short, indoor air is dry, and there are no natural predators for houseplant insects. But it is possible to overwinter your tender tropical plants. Here are three ways to do it and which plants are best for each method.
Storing Tropical Bulbs and Tubers
Many gardeners start their elephant ears from bulbs but don't consider digging them up and storing them indoors for the winter. This is arguably the easiest way to overwinter plants and the bulbs of tuberous plants such as cannas, caladiums, and even dahlia tubers are good candidates for overwintering indoors. You need to wait until the foliage has been killed by a light frost, then lift the plants and put them somewhere shaded and sheltered, so the bulbs can dry out for several days.
Note: Dahlias tubers must be left in the ground for 10 days after a killing frost before you can dig up the tubers.
Once dry, brush off as much soil as you can, trim the leaves back to a couple of inches, and store them in a box filled with peat moss or sawdust or wrap each bulb in a sheet of newspaper and tuck them into a box. Keep them cool and in the dark, checking periodically to see if any are starting to rot or if they are starting to shrivel. Dispose of any rotting bulbs and spray a little water onto the peat or paper if they are drying out.
To get a head start on the next growing season, you can pot up the bulbs indoors a month or two before your last frost. Or, you can plant them outdoors as soon as the ground warms and no frost threatens. This method takes up minimal space and most bulbs and tubers make it through the winter just fine. Beause the bulbs will produce more offset bulbs, saving them year after year will also mean more bulbs each year to plant or give away.
Bringing Tropical Plants Indoors
Not all tropical plants make good houseplants, but there are plenty that do. Some, such as canna, seem to attract and carry every aphid indoors with them. And very often you just don't have the growing conditions a tropical plant needs to continue growing and looking attractive indoors. If you want to give it a try, start caring for them before you bring them inside. Carefully inspect the plants for any sign of pests or disease and treat accordingly. You might want to cut it back by one-third to one-half, to make it a more manageable size.
Then find the brightest window you have and make a space for your plants to settle in. Make sure they are away from drafts and from excessive heat sources. Bringing your plants indoors while the windows are still open at night will give them the best chance of acclimating.
If your home doesn't have a sunny window, you can use artificial plant lights. Another concern for growing tropical plants indoors is the dry air in winter. Keep a spray bottle handy, and mist your plants daily.
Some great candidates for growing indoors in winter include angel's trumpet, banana, begonia, fuchsia, and mandevilla. Your plants probably won't thrive and they may not bloom, but they should survive with minimal stress.
Letting Tropical Plants Go Dormant in Containers
This method of overwintering tropicals is a little more hit-and-miss than simply storing them as bulbs, but it's worth a try. It helps if the plants are already in containers, but you can always lift them and pot them up at the end of summer.
After a light frost, cut the tops of the plants back to six to eight inches and only water when the soil looks bone dry. The plants should be moving into dormancy and won't need water for a while.
Move the containers to a cool, dark spot that will remain above freezing, but below about 50 degrees Fahrenheit. Check moisture periodically, but water sparingly if dry. You can resume regular watering about the same time you begin to start seeds indoors. At that point, you should see new growth starting and you should move the containers back into the light. (Don't move them directly into bright light immediately or you could burn the tender, new leaves). When you see several inches of new growth, apply a light does of fertilizer. Begin to harden off the plants, after the danger of frost has passed.
Plants that can handle this type of winter care well include angle's trumpet, banana, begonia, caladium, canna, mandevilla, and tender ornamental grasses.