Gladiolus Corms

Gladioli or sword lilies are hot weather flowering plants that have been extensively hybridized for their colourful blooms. The corms of most species and hybrids should be lifted after the leaves die down naturally in autumn and stored over winter in a frost free place, then replanted in spring in temperate regions. The Nanus hybrids are much hardier to at least −26 °C or −15 °F and can be left in the ground in regions with sufficiently dry winters.
Gladiolus is propagated from small cormlets produced as offsets by the parent corms or from seed. Clumps should be dug up and divided every few years to keep them vigorous in hot climates where they grow as perennials.