Bright geraniums perk up a summer garden. These colorful annuals are some of the most popular flowering plants because they grow easily in full sun and don’t require much water. If you’d like more geraniums in your garden, or if you’d like to overwinter a favorite cultivar, it is easy to start new plants from cuttings.
You can easily propagate geranium plants by cuttings in the spring or summer. Place the cuttings, which should be 2 or 3 inches long, in vermiculite or any well-drained sterile soil mix with a plastic bag covering the pot. Once you see roots, open the bag and slowly move the new plant into full sunlight over a period of several days, advises Deborah L. Brown and Harold F. Wilkins of the Department of Horticultural Science at the University of Minnesota.
You can overwinter geranium cuttings and have vigorous plants ready for potting in early spring. Make the cuttings from healthy mother plants about four weeks before the first frost. After you root the cuttings in a coarse, sandy medium and water them well, keep them in full sun. Overwintered cuttings need only enough water to keep them from shriveling. Fertilize them with a water-soluble formula every two weeks.
Geranium cuttings are susceptible to several diseases. Control black leg and black stem rot by taking cuttings only from healthy plants that have been kept dry, using sterilized rooting medium and sterilizing your cutting tools. As viral diseases can transmit from infected plants to new cuttings, do not take cuttings from any plant with mosaic, distortion or leaf spots, warns Alice B. Russell of the North Carolina Cooperative Extension.