Not all geraniums are true geraniums — the common summer pot plant known as geranium is actually a pelargonium. True geraniums, also known as cranesbills, are hardy perennials from the genus Geranium. These dependable plants grow well throughout much of the United States. Flowers are pink, red, white or blue, and the foliage on some varieties turns red in fall. Plant hardiness depends on the cultivar, so read the label information carefully before choosing.
Things You’ll Need
- Organic material
- All-purpose flower garden fertilizer
- Fungicide (optional)
- Sharp knife, for division
- Cranesbills get their name from the shape of the seeds.
Site cranesbills in full sun to light shade, in moist, well-drained soil. Amend the soil with organic material, such as well-rotted manure or compost, if necessary.
- Water geraniums often enough to keep the soil moist, but not soggy. These plants are drought-tolerant once established.
- Fertilize cranesbills in early spring and again after the first flush of flowers. Follow package application rate directions carefully. Sprinkle the fertilizer over the root zone and water well.
- Deadhead spent flower stalks to encourage reblooming. Cut flower stalks back to a leaf node, or all the way to ground level if there aren’t any leaves.
- Inspect leaves for leaf spots during hot, humid weather. Unless the plant is badly infected, leaf spots are not a serious problem, according to Iowa State University. If necessary, control this fungal disease by spraying with a fungicide or by cutting back the plant.
- Shear plants to 6 to 8 inches from the ground if they become leggy or are infected with leaf spot. The plant will put out a new flush of leaves and flowers.
- Cut off withered leaves after frost. This prevents disease spores from overwintering in the garden.
- Divide overgrown plants in spring. Dig up the entire plant and wash soil off the roots with a garden hose. Cut the roots into fist-sized sections, discarding the center of the plant if it’s dead and leafless. Replant new divisions as soon as possible. Keep them well-watered during the first growing season.
Tips & Warnings
You can discourage fungal diseases like leaf spot by watering only at the base of the plant, being careful to keep the foliage dry.