How Do Geraniums, Rosemary, and Roses Overwinter? A Guide to Getting Perennials and Tropical Plants Through the Winter
Learn how to properly overwinter your garden plants to protect them from snow, wind, and freezing temperatures. They will thank you in the spring!
How to overwinter geraniums:Before the first frost (find your area's frost dates here), cut the plant back to about 6 to 8 inches. Then lift the plant and cut off the roots. Place the trimmed plant in the smallest pot - a container large enough to hold the roots. Fill the remaining space in the pot with regular potting soil. Keep the plant in a cool place for a week, then place them in a sunny spot indoors. When new growth begins, cut off all the old leaves.
How to overwinter rosemary:This culinary herb prefers to live in a pot and can successfully survive year after year as a houseplant.Before it frosts in the fall, dig it up, put it in a pot, and bring it indoors. Place it in a sunny window and keep it evenly watered. Mist the leaves often or put the whole plant in the shower to rinse it once a month. By March, the plant may start to look a little tired, but once you return it to the garden, it will perk up. After all danger of frost has passed, in late spring dig a hole and put the plant back in the soil.
How to overwinter roses:Roses need a thick insulating layer to help them stay dormant. For those that are grafted, such as hybrid teas, make sure their graft union is covered with soil to insulate them from low temperatures. After one or two freezes, pile 12 inches of soil around the base of the rose bush.Non-grafted roses, such as rugosas and antique roses, do not need much protection. Cover the ground around them with a few inches of straw or shredded leaves.
All climbing roses need protection. Pull down the canes, lay them on the ground, and cover them with at least 6 inches of soil. Also mound soil around the base of the plant. If your winter temperatures drop below -10°F, leave the canes in place and wrap them with burlap or old sheets over a thick layer of straw.
How to overwinter perennials:To encourage your perennials, especially new plants, to go dormant and stay that way through the inevitable freeze-thaw cycles of winter, you can apply mulch such as straw, leaves, or other organic matter after the first few hard frosts. If you mulch the ground too early in the fall, rodents may find the cozy layer impossible to resist, and the mulch may also keep the ground frozen solid. See our article on getting your perennial garden ready for winter.
How to overwinter tropical plants:Many tropical plants grow from underground bulbs, corms, or tubers, including fritillaria, calla lilies, cannas, dahlias, ginger, and tuberous begonias. These plants are easy to overwinter. When nighttime temperatures drop below the 40s or 30s, the plant's leaves turn brown and begin to die. This is your cue to dig or lift them. (You can wait until a killing frost before digging dahlias and cannas.)
Remove dirt from the swollen root portions, place them on newspaper in a shaded area or garage to cure for a few days. Cut off the top growth, and pack the bulbs, corms, and tubers into boxes filled with dry peat moss or vermiculite. Store in a dark area with temperatures between 35° and 50°F.
When spring arrives, plant them again for another year of enjoyment. When saved this way year after year, bulbous tropical plants will increase their numbers and produce larger bulbs, corms, and tubers.
