Crocosmia are perennial plants native to tropical parts of Africa. There are around 400 cultivars of the various species, according to Washington State University. Crocosmias grow from corms, a type of flower bulb, and spread quite rapidly. The brightly-colored orange, yellow and red flowers are a favorite with nectar-loving insects and with hummingbirds.
Crocosmias have red and orange flowers, or in the case of hybrids, red, yellow and orange flowers. The flowers dangle from a tall, slender stalk that arches gently at the tip. The leaves and flower stalk can get quite long--up to 3 feet, according to Washington State University, The leaves are thin and sword-shaped. The color of the foliage varies from bright green to light green, depending on the cultivar.
Crocosmia flowers thrive in climates with warm summers and cool winters. They need a cooling period to bloom the next year. Crocosmias usually grow best in U.S. Department of Agriculture (USDA) plant hardiness zones 5 to 9, according to North Carolina State University.
Crocosmias thrive in rich, well-draining soil. These flowers need a location exposed to a full-day's worth of sunlight--save in the hottest climates--to bloom well, according to North Carolina State University. Clumps should be dug up in early spring and divided every 2 to 3 years.
Plant crocosmia flowers when all danger of frost has passed. Separate each corm from the next by about 7 inches. Plant them 4 inches deep, and keep the soil moist, but not soggy, until they bloom. These plants look best when grown in groups of the same cultivar, according to Washington State University.
Species and Cultivars
Crocosmia X Crocosmiiflora, or "Lucifer", is the most commonly grown crocosmia in home gardens, according to the University of Arkansas. "Lucifer" flowers are bright orange and very hardy. It is sometimes called "Montbretia." Crocosmia x crocosmiiflora "Emberglow" is a cold-hardy cultivar that has bright red flowers on long, 40-inch stems. Crocosmia x crocosmiiflora "Solfatare" has unusually-colored leaves, which are bronze, and yellow flowers that bloom late in the summer. This cultivar grows to a height of 3 feet.