Most plants that we call “annuals” are actually tender perennials that can’t survive winters in colder climates. We treat them like annuals, cast them on the compost heap in the fall and buy new ones the following spring.
Last summer I purchased a lantana at our local garden center. It was a mature flowering plant in a large 14-inch container, and it cost me $50. At that price I decided I wanted to treat it like the perennial it is and overwinter it in my greenhouse. Lantana is not the least bit frost tolerant, so as soon as outdoor temperatures threatened to drop to freezing, I brought it indoors. As the greenhouse got cool the leaves started to die back and drop off. I cut the plant way back (See the photo below.) and let it rest for the remainder of the winter. There were some leaf sprouts, but they did not amount to much.
This spring, as soon we were past the danger of a frost (Memorial Day weekend is usually the demarcation in our area), I put the plant outdoors again, and it grew leaves and blossoms quickly (The opening photo was taken this summer, year 2.).
A few other considerations:
If you don’t have a greenhouse—During the winter months when your plant is dormant, it will be OK if it is situated indoors in indirect sunlight. However, as soon as it begins to break dormancy in late February or March, it needs to be placed in a sunny window in direct sunlight.
Spider mites—My lantana developed spider mites, but I was able to control them by gently wiping the webs off the branches periodically and lifting any dead leaves off the soil in the container. A miticide can help to control them, too. Spider mites are an inevitable result of moving a plant indoors that has been outdoors all season. Once the plant has been moved back outdoors again in the spring, nature’s defenses take over, and spider mites are usually no longer a problem.
Fertilizing—I didn’t fertilize my lantana until it showed signs of breaking dormancy in late February. You don’t want to fertilize while it is dormant because it stresses the plant. Like most perennials it needs to rest.
Watering—While your plant is dormant, water it sporadically. Once it begins to grow in early spring, you can water it as needed.
Here is a list of some other tender perennials that we treat as annuals in colder climates:
Canna (Cannaceae spp.)
Cleome (Cleomaceae spp.)
Dahlia (Coreopsideae spp.)
Heliotrope (Heliotropium spp.)
Lantana (Verbenaceae spp.)
Marguerite daisy (Argyranthemum spp.)
Scaevola (Goodeniaceae spp.)
Scutellaria (Lamiaceae spp.)
Snapdragon (Antirrhinum spp.)
Verbena (Verbenaceae spp.)
Zinnia (Asteraceae spp.)
Dorian Winslow is the president of Womanswork, and is passionate about making the best products on the market for women who garden and work outdoors.
Horticulture publishes the free weekly e-newsletter, “Smart Gardening Tips,” and “The Curious Gardener,” a free monthly e-newsletter with more tips and articles by Dorian. Subscribe to our e-newsletters.