Geraniums are popular bedding plants, blooming freely from May to frost. However, the first hard frost doesn't have to be the end for your geraniums. They can be overwintered by potting up individual plants, by taking cuttings, or by hanging the plants upside down in a cool, dry place.
Potted Plants. Prune the geraniums back to 1/2 to 1/3 of their original height. Then carefully dig each plant and place in a 6-to 8-inch pot. After potting, water thoroughly and place the plants in a bright, sunny window. Geraniums prefer cool indoor temperatures. Daytime temperatures near 65 F and night temperatures around 55 F are ideal. (Geraniums become spindly when grown in poor light and warm temperatures.) During their stay indoors, water the plants thoroughly when the soil is dry to the touch. Occasionally pinch or prune the geraniums to maintain stocky, well-branched plants.
Cuttings. Using a sharp knife, take 3- to 4-inch cuttings from terminal shoots. Pinch off the lower leaves, then dip the base of the cuttings in a rooting hormone. Stick the cuttings in a rooting medium of vermiculite, coarse sand, or a mixture of coarse sand and sphagnum moss. Clay or plastic pots with drainage holes in the bottom are suitable containers. Insert the cuttings into the medium just far enough to be self-supporting. After all the cuttings are inserted, water the cuttings and medium thoroughly. To prevent wilting, place a clear plastic bag over the cuttings and container. Then place the cuttings in bright light,but not direct sunlight. Rooting should occur in 6 to 8 weeks. Plant the rooted cuttings in 3- or 4-inch pots containing a well-drained potting soil. Care of the rooted cuttings is the same as for the potted plants.
Dormant Plants. Dig the geraniums and carefully shake all the soil from the roots. Then hang the plants upside down in a cool(45-50 F), dry place. During the winter months, periodically take the plants down and soak the roots in water for 1 to 2 hours. Most of the leaves will fall off during the winter. However, the stems should remain firm or solid. Cut back the geraniums to 1/3 their original height and pot indoors in late winter or plant outdoors in May. This method of overwintering requires proper storage conditions.
This article originally appeared in the September 16, 1994 issue, pp. r 16, 1994 issue, pp. 140-141.