Unless they live where winters are frost-free, gardeners treat geraniums (Pelargonium spp.) as annuals, discarding plants each fall and planting new ones each spring. There's always a new color or foliage form. If you find a plant you like, start new plants from cuttings rather than discarding the plant or nursing it through winter. You'll need starter mix, plastic bags, rooting hormone, a sharp knife and a sunny windowsill.
Garden geraniums (Pelargonium x hortorum), ivy geraniums (Pelagonium peltatum) and scented leaf geraniums (Pelargonium spp.) are all easy to start from cuttings. They are tender perennials, hardy in U.S. Department of Agriculture plant hardiness zones 10 and 11. Keep the plastic pots your geraniums came in from the nursery for cuttings, and pinch plants back all summer long to encourage compact growth and bloom. By August or early September, you should have big, bushy plants with plenty of soft green growth.
Mix any of the following -- vermiculite, perlite or peat moss -- half and half with clean, sharp sand to make a fast-draining starting medium that will hold the cuttings upright. Use nursery pots or any pots with drainage holes on the bottom that will fit inside a gallon-size plastic bag. Purchase a starter rooting hormone powder -- there are several available. Use a dish for dipping cut ends. Make a mixture of rubbing alcohol mixed 50-50 with water or hand sanitizer, and use it to clean cutting tools periodically to avoid spreading pathogens from one pot to the next.
Bring geraniums in when nighttime temperatures fall below 50 degrees Fahrenheit and before central heating kicks in. In cooler areas, pot them up and bring them in at least a week before the furnace goes on for the first time, so they can acclimate to the drier indoor air. Put the plants in a sunny window and keep their soil moist, not soaked. Fill pots with starting medium and tap the pots to settle the contents.
Take 3- to 5-inch cuttings from growing branch tips, cutting below a knobby “node” where leaves sprout. Nonflowering cuttings root most easily, but you can also root flowering branches -- just pinch off flowers at the stem. Pinch or cut all the leaves from the cutting, leaving only three to four leaves on its end. Lightly touch the cut end to the powder in the dish; make a hole in the medium with a pencil, and plant the cutting. You can put several “starts” in one pot, but don't let their leaves touch.
Place your starter pots on a tray and water the medium until moist. Cover each pot with a plastic storage bag -- supported with a straw to keep the plastic off the leaves. Put your mini-nursery in a bright, warm place to root. If condensation forms on the bag, air out the plants. Check for soil moisture weekly, and sprinkle when necessary. In four to six weeks, or when cuttings resist a tug, they're mature enough to pot individually in a potting mix and put on a sunny window ledge until spring.
- Missouri Botanical Garden: Pelargonium X Hortorum
- Missouri Botanical Garden: Pelargonium Peltatum
- Missouri Botanical Garden: Pelargonium (Scented-Leaved Group)
- Missouri Botanical Garden: Pelargonium X Domesticum
- University of Nebraska at Lincoln Backyard Farmer: Overwintering Geraniums and Propagating Geraniums by Cuttings
- University of Vermont Extension: Rooting Cuttings