How Long Do Geraniums Last?

Climate

• Hardy geraniums are temperate plants. Although they vary by species and cultivar, most are hardy in U.S. Department of Agriculture plant hardiness zones 5 through 8. Some have roots that will tolerate temperatures as cold as those in USDA zone 3, although even with a protective layer of mulch, the above-ground vegetation may die. Others can tolerate the hotter summers of USDA zone 9.

Culture

• Sooner Plant Farm describes these plants as "long-lived," but no plant lives for long if it isn't cared for correctly. Rich, well-draining soil is best for these geraniums. They prefer moist soil, which stimulates rapid growth and increases the vigor of the plants, according to the University of Vermont. Too much water, however, can cause root rot and other problems. In warmer climates, hardy geraniums need some protection from afternoon sun, but home gardeners who live in cooler climates can grow the plants in full sunlight.

Selected Species

• Geranium sanguineum tolerates the hottest temperatures of all the species and can even withstand periods of drought. It grows best in USDA zones 3 through 8 and features pink flowers streaked with hotter pink threads. Geranium himalayense is hardy in USDA zones 4 through 7 and is best known for its colorful fall foliage, which turns red and orange when autumn arrives. The spring-blooming flowers are bluish-purple. Geranium macrorrhizum is hardy in USDA zones 3 through 8 and features scented foliage with magenta spring flowers.

Considerations

• Plants in the Pelargonium genus are often commonly called geraniums. Although they are part of the Geraniaceae family, they are not true geraniums. True geraniums have five, equal-size petals on each flower, whereas flowers in the Pelargonium genus vary. Unlike true geraniums, flowers in the Pelargonium genus are not frost-hardy. Most are perennials in USDA zones 10 and 11 only, although some cultivars may be able to tolerate cooler climates. In these zones, they can last for several years. Home gardeners in cooler climates often grow pelargonium plants as annuals, in which case they last for only one year.