Gladiolus

A tall, summer-growing cormous perennial from across sub-Saharan Africa, grown for arching spikes of large, hooded, orange-to-red-and-yellow flowers in summer over fans of sword-shaped leaves. This is the widespread wild African gladiolus and a key ancestor of the big garden gladioli. Unlike the winter-growing Cape bulbs, it is a SUMMER-GROWING corm: plant in spring, grow and flower through summer, then it dies back to a dormant corm for winter. It wants full sun, well-drained soil, and summer moisture, and is one of the hardier species gladioli — surviving to about USDA zone 7 with a deep winter mulch or by lifting the corms in cold-winter areas. The corms are toxic and irritant if eaten and have been used in traditional medicine, never as food. In the wild the hooded flowers are pollinated by sunbirds and long-tongued insects.

The classic "sword lily" of the summer cut-flower garden — a corm-grown hybrid (commonly designated Gladiolus × hortulanus) descended from at least eight mostly South African species. Sword-shaped leaves rise in upright fans below a one-sided spike of funnel-shaped blooms that open bottom-to-top in nearly every color but true blue. Showy and fragrant but not winter-hardy outside zones 7-10: in colder gardens the corms are lifted and stored frost-free.