A genus of 180 species and over 10,000 cultivars, Acidanthera are cormous perennials, mainly from South Africa, that are grown for their showy, open funnel-shaped flowers that bloom from spring to early autumn, depending on the species. Flowers open from the bottom of the spike to the top. Iris-like leaves in fan formation can grow from 10 to 36 inches long. They are best planted in clumps in a border or in rows in a cutting garden. Tender species can be lifted and stored over winter. There are three main classifications: Grandiflorus, Nanus, and Primulinus.
Noteworthy CharacteristicsShowy spikes of flowers, in nearly every color of the rainbow. More than 10,000 cultivars are available.
CareGladiolus need fertile, well-drained soil in full sun or part shade. Plant in spring, placing the corms 3 to 6 inches deep and just as far apart. To extend the bloom season, make successive plantings. Lift corms of tender species 6 weeks after bloom, cut off the foliage, dip the corm in fungicide, and dry for a few weeks. Then store in a dry and frost-free location.
PropagationIf species is hardy, sow seed in containers in a cold frame in spring. If tender, sow seed at 59°F in spring. Separate cormlets when dormant.
ProblemsGladiolus corm rot, gray mold, viruses, aster yellows, spider mites, thrips, and aphids.