Geraniums, also known as storksbills, are flowering perennials valued for their large, scented flowers. Native to South Africa, geraniums are hardy in USDA zones 4 through 8 and thrive in most regions of the United States. Geranium flowers appear in shades of white, red, pink or purple, depending on variety. The flowers bloom during early summer and last until temperatures begin to drop in the fall. Geraniums are susceptible to numerous diseases, though these can easily be prevented if proper care is maintained.
Plant geraniums during spring after all danger of frost has passed. Choose a location that consists of well-drained, fertile soil and receives full sunlight for optimal growth. Space geraniums 24 to 36 inches apart.
Spread a 3- to 4-inch layer of mulch over the soil surrounding geraniums to increase moisture retention, insulate the soil and deter weeds. Replenish the mulch as often as necessary to keep it at least 3 inches thick. Allow about 3 inches between the crown of the plant and the mulch to reduce the risk of fungal diseases.
Water geraniums thoroughly immediately after planting. Decrease watering frequency to once every 10 days thereafter, allowing the soil to dry between applications. Do not splash water on the foliage, as moist leaves are more susceptible to developing rot or other diseases.
Feed plants once every four to six weeks using a 10-20-10 NPK water-soluble fertilizer to provide adequate nutrition. Apply at the rate recommended by the manufacturer's directions for the best results. Water after feeding to prevent root burn.
Remove dead, discolored and faded geranium flowers to encourage the formation of new blossoms and extend the blooming period. Pinch off the flowers near the base of the stem to reduce damage to the plant and reduce the chance of disease.