Every fall, millions of geraniums end up on the compost pile after the first frost. It doesn’t have to be that way. With one simple move before the cold arrives, the same plants can spend the winter safely and flower again next year.
In short
- Geraniums must be brought indoors or dug up before the first frost.
- Extension experts describe three methods: as houseplants, as cuttings, or dormant and bare-root.
- Bare-root plants are stored at about 45 to 55°F and cut back in March.
- Check plants for pests and diseases before bringing them inside.
Timing is everything
“Geraniums must be dug or moved indoors before the first frost, so don’t wait until the last minute,” warns Ken Johnson, horticulture educator at University of Illinois Extension. Before bringing them in, inspect each plant. Discard any with spots, wilting, rot or insects, since they’re hard to overwinter and can spread problems to other plants.
The good news, according to University of Wisconsin Extension: “Overwintering them is not difficult and there are three basic methods on how to do it.”
Method 1: keep them as houseplants
Pot the plants in a container with drainage holes, prune them back by one-third to one-half, and water thoroughly. Place them in a bright, sunny window. They “fare much better in cooler temperatures (60 to 65 degrees F),” Wisconsin Extension notes, so keep them away from heat vents and fireplaces. Water when the soil feels dry, and pinch back leggy stems.
Method 2: take cuttings
Cut 3- to 4-inch stem tips, remove the lower leaves, dip the ends in rooting hormone and insert them in perlite, vermiculite or a sand and peat mix. Keep the medium moist under bright light. Roots typically form in 4 to 8 weeks, says Illinois Extension. A clear plastic bag over the pot can help keep moisture in, but watch for mold. Then move each cutting into a small 3- to 4-inch pot until spring.
Method 3: the old bare-root trick
This is the method many grandparents used. Dig up the plants, shake the soil off the roots and store them in a large paper bag, or hang them upside down, in a cool, dry place at about 45 to 55°F: a basement, an unheated room or a garage that doesn’t freeze. “Don’t be surprised when the leaves start to dry up and fall off,” Wisconsin Extension says. To keep the roots from drying out, you can soak them in water for a few hours, several times over the winter.
In March, cut the plants back to firm, green tissue, pot them, water well and treat them as houseplants until they go outside in May. Fall is a busy season in the yard, from knowing when to stop mowing to setting up a rain barrel.
The limit
Not every plant survives the winter, especially with the bare-root method, and results depend on how cool and dry your storage space is. These tips apply to the common garden geraniums, which botanists call Pelargonium, not to hardy perennial geraniums that stay outdoors.
That’s the trick.
