- Gladiolus are recommended for USDA hardiness zones 7 through 9. The Northern gardener can enjoy the beauty of gladiolus in the summer garden when the corms are set into the ground starting in mid-May. It takes three months for the flower shoot to appear, and the gardener can estimate the desired bloom time and adjust the time of planting.
- Extend the time that gladiolus beautify the garden by planting the corms every two weeks until the middle of June.
- Larger gladiolus corms will produce plants that bloom in less time than smaller corms. If the corm has a diameter of less than 3/4-inch when planted, it may not produce any blooms at all.