You Can Overwinter Geraniums

Last Updated: September 23, 2008 | Related resource areas: Gardens, Lawns & Landscapes

Released September 22, 2008

http://www.extension.iastate.edu/news/2008/sep/061902.htm

Contacts: Richard Jauron, (515) 294-1871, rjauron@iastate.edu

Del Marks, (515) 294-9807, delmarks@iastate.edu

AMES, Iowa – Geraniums are popular flowering plants, blooming from May through frost. However, you don’t have to let the first hard frost destroy your geraniums. Geraniums can be overwintered indoors by potting up individual plants, taking cuttings, or storing bare-root plants in a cool, dry place. Regardless of the method, the plants should be removed from the garden prior to the first frost.

Potted Plants

Carefully dig up each plant and place in a large pot. Water each plant thoroughly, then place the geraniums in a bright, sunny window or under artificial lighting. Geraniums prefer cool indoor temperatures. Daytime temperatures of 65 to 70 degrees F and slightly cooler night temperatures are ideal. During their stay indoors, water the plants thoroughly when the soil becomes dry. The geraniums are likely to become tall and lanky by late winter. In March, prune back the plants. Cut the geraniums back by one-third to one-half. The geraniums will begin to grow again within a few days and should develop into nice specimens by May.

Cuttings

Using a sharp knife, take 3- to 4-inch stem cuttings from the terminal ends of the shoots. Pinch off the lower leaves, then dip the base of each cutting in a rooting hormone. Stick the cuttings into a rooting medium of vermiculite or a mixture of perlite and sphagnum peat moss. Clay or plastic pots with drainage holes in the bottom are suitable rooting containers. Insert the cuttings into the medium just far enough to be self-supporting. After all the cuttings are inserted, water the rooting medium. Allow the medium to drain for a few minutes, then place a clear plastic bag over the cuttings and container to prevent the cuttings from wilting.

Finally, place the cuttings in bright light, but not direct sunlight. The cuttings should root in six to eight weeks. When the cuttings have good root systems, remove them from the rooting medium and plant each rooted cutting in its own pot. Place the potted plants in a sunny window or under artificial lighting until spring.

Bare Root Plants

Dig the geraniums and carefully shake all the soil from their roots. Then place one or two plants in a large paper sack and store in a cool (45 to 55 degrees F), dry location. An unheated bedroom or indoor porch might be a suitable location. An alternate (somewhat messier) method is to hang the plants upside down in cool, dry location. The foliage and the shoot tips will eventually die. In March, prune or cut back each plant. Remove all shriveled, dead material. Prune back to firm, green, live stem tissue. After pruning, pot up the plants and water thoroughly. Place the potted geraniums in a sunny window or under artificial lighting. Geraniums that are pruned and potted in March should develop into attractive plants that can be planted outdoors in May.

The overwintered geraniums can be planted outdoors in May (after the danger of frost is past). Before planting, harden or acclimate the geraniums outdoors for several days. Initially, place the geraniums in a shady, protected location and then gradually expose the plants to longer periods of sunlight. Plant the geraniums in the garden after the plants have been properly hardened.