Gladiolus plants grow from stem structures called corms. They reproduce by means of small corms, called cormels, that form at the base of the corms. Another method of propagating gladiolus is by division of mature corms.
Corms look similar to bulbs but have some important differences. Each year, the mother corm shrivels as its carbohydrates and nutrients are expended, and a new corm forms in its place. The cormels that develop at the base of the corm grow into mature corms over a period of a few years.
Divide corms that have more than one bud at the top. At planting time, use a sharp knife to divide the bulb as equally as possible. Each half should have one bud.
Remove cormels that are dime-size or larger from the base of the corm, Store them over winter in an open box or jar. Before replanting in spring, soak them in water overnight. Plant them 1 to 2 inches deep and keep the soil moist until the plants emerge. It takes two to three years for cormels to produce flowers.