Gladiolus can be propagated by dividing corms or by harvesting seeds.
Dividing corms
Dig up corms: At the end of the growing season, dig up the gladiolus corms.
Remove cormlets: Gently separate the baby corms, called cormlets, from the main corm.
Store cormlets: Keep the cormlets in a dry place over winter.
Plant cormlets: In the spring, plant the cormlets in a separate area.
Dig up again: In the fall, dig up the cormlets and store them again over winter.
Replant: In the spring, replant the cormlets and they should flower in their second year.