It can be difficult to say goodbye to garden flowers that are particularly unique or well-loved, but winter generally brings an end to the flowering annuals that you’ve enjoyed outdoors all summer. Luckily, several varieties can be overwintered. Given enough light and the right care, these annuals can thrive during the cold season and move outdoors once more come spring.
Not all annuals will overwinter, unfortunately. Among the true annuals that will, however, are fibrous, or wax, begonias (Begonia semperflorens), geraniums (Geranium spp.), impatiens (Impatiens spp.) and coleus (Solenostemon scutellarioides). Others that can be overwintered are perennial in warmer climates. These include bougainvillea (Bougainvillea spp.), which grow well in U.S. Department of Agriculture plant hardiness zones 9 through 11, and fuschia (Fuschia spp.), which are winter-hardy in USDA zones 10 through 11.
Fibrous begonias, geraniums, impatiens and coleus are somewhat easier to prepare for colder months by cutting stems back to half their height and repotting them before bringing them inside to a warm location. A bit more difficult are plants like bougainvillea and fuschia, but with carefully timed moves to cooler and warmer locations, you can sometimes get them to bloom again.
When to Move
Move begonias, geraniums, coleus and impatiens indoors before the first expected frost. Dig them up, cut back, repot and bring them inside to a well-lit location. Be sure to do it while you still have several weeks to spare; if they have pests and need to be removed to the outside for treatment, you don’t want the weather to be too cold. Fuschia and bougainvillea should also be brought inside before the frost. All plants can be moved back outdoors in spring, after danger of frost has passed and they have been hardened off.
Fuschia should be put in a 40- to 50-degree Fahrenheit location and pruned in February. Bougainvillea does best when trimmed in fall and placed in a cool location until March, when you can water it and prepare it to move outdoors. Begonias, geraniums, coleus and impatiens, however, should be watered and kept in houseplant conditions -- room temperature -- and pinched so that they do not get straggly. If plants start looking leggy, you might need to increase their light intake with fluorescent tubing.
Moving plants to warmer or cooler locations abruptly can shock and even kill them. Any time you move a plant indoors or out, let it spend several hours a day in its new environment before moving it back to the old one. Do this for about a week to make sure plants develop tolerance that will keep them healthy. Any time you bring plants indoors, check carefully for pests before bringing them inside, and keep them in a separate location for a while.
- Iowa State University Extension and Outreach: Annual Flowers for Indoor Use
- Washington State University Extension: Overwintering Tender Annuals and Houseplants
- University of Nebraska-Lincoln Extension in Lancaster County: Overwinter Flowering Annuals
- Colorado State University Cooperative Extension: Hardening Off Isn't Hard
- Missouri Botanical Garden: Bougainvillea Group
- Missouri Botanical Garden: Fuschia Group
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