Overwintering geraniums

Carol Bray
Isanti County Master Gardener

Many gardeners like to keep their geraniums from one year to the next—sometimes for the challenge, sometimes to keep costs down and sometimes to simply be more “green.”

Many gardeners like to keep their geraniums from one year to the next. Photo by Carol Bray

South African in origin, geraniums (pelargoniums) have a three-month dormant period during winter’s dryness. There are several methods of handling geraniums over winter.

One way is to take cuttings and root them, early in fall. Geranium stem cuttings, often called “slips,” should be about four inches long. Take the slips from the tips of the healthiest stems. Remove the leaves on the bottom two inches of the cuttings. Stick the cuttings in a coarse sand, perlite, vermiculite or a well-drained potting soil. Cuttings would root faster if you dip the ends in rooting hormone powder. Stick the cuttings two inches deep in the medium and water thoroughly. Place in a north or east window or underneath artificial lights until rooted. This generally takes three to four weeks.

After the cuttings have rooted, plant them in individual pots and put them in a well-lighted spot. Keep the soil evenly moist and fertilize lightly every four to six weeks once new growth appears.

Or, you may prefer to pot your best plants and bring them indoors for winter. Cut the plant back to about one-third its original height. Carefully dig up the plant, and pot it into a six-inch or larger flowerpot. Water thoroughly and put it by a sunny window.

Yet another (old) method of carrying geraniums over winter is to dig the plants, shake excess soil from their roots, and then hang them from your basement rafters. This method works best if the location is dark and cool (around 50 degrees F.)  Take the plants down occasionally and place the roots in water for several hours. Then, hang them back up. Do this several times over the winter to prevent them from drying out completely. Pot your geraniums in early spring, and put them in a sunny window until frost danger has passed. It is also possible to overwinter your geraniums by keeping them in plastic or glazed pots with good drainage and giving them very little water. In spring, bring them into a warm place and water them heavily.

I would recommend trying several methods and see which one(s) work best for you. For more information, visit the U of M Extension website, www.extension.umn.edu or call the Isanti County Master Gardeners at 763-689-1810.