Gladiola or gladiolus grows 2 to 6 feet high with spikes bearing a double row of trumpet-shaped flowers and swordlike leaves. Flowers are 1 to 8 inches in diameter and are produced in a wide range of colors.
Bulbs and Corms
"Bulb" is a general term used to describe fleshy underground organs that some plants use to store nutrients during winter. A gladiolus bulb is technically a corm, which is a mass of tissues at the base of a stem that stores nutrients.
Gladiolus corms are planted in late winter or early spring. The North Dakota State University Agriculture and University Extension says soil type and size of corms determine the spacing and depth of planting. In general, corms are planted deeper in sandy soils and shallower in heavy soils.
The extension advises planting large corms 6 inches deep and 6 inches apart; medium corms 4 to 5 inches deep and 3 to 4 inches apart; small corms 3 inches deep and 2 inches apart; and cormels (pea-sized, newly formed corms) 1 to 2 inches deep and 1 to 2 inches apart.
Gladiolus corms must be dug up and stored each fall, then replanted in the spring after danger of frost has passed.