When Do Gladiolus Flowers Bloom?

Call these tall, upright bulb plants gladioli, glads, sword lilies, or even Aunt Eliza's rat's rail, but they will remain a garden favorite. This genus of flowering bulbs produces tall, brightly colored flower spikes and sword-shaped green leaves in upright fans. Expect blooms to come in about midsummer and last through fall.

Gladioli are bulb plants in the Iris family that produce impressive flower spikes of bright, funnel-shaped blooms. The flowers are fragrant, and they form beautiful, long-lasting cut flower bouquets. Their color range is vast, and several sizes are available, making glads particularly versatile in flower arrangements.

"Sword lily" is one of the plant's many common names. It comes from the shape of the long, thin, dark-green leaves. Exotic cultivars are available, but most home gardeners go for either the popular large-flowered gladiolus — with big, showy blossoms that can be frilled, ruffled, or plain — or miniature glads. The miniatures look just like the large-flowered types but are smaller and perfect for more compact arrangements.

Although glads are known as bulb plants, the structure from which they grow is actually a corm, a swollen underground stem designed to store food. The corm's job is to keep the plant alive during winter dormancy so it can grow again in spring.

When you are first planting glads in the garden, it's very important to select healthy corms that are smooth, firm, and undamaged. That's the best way to ensure vigorous plants. Plant the corms in loamy or sandy soil because drainage is critical. Pick a site that gets good sun but is relatively far from shrubs or trees.

Corms should be planted in spring and early summer. They can go into the ground up to a month before the last frost date, but planting should be completed by early July. Place the corms between 2 and 6 inches deep, with larger bulbs deeper than smaller ones. Bigger plants will need staking to keep their stems upright.

Gladiolus is an easy-to-grow flower in warmer zones like U.S. Department of Agriculture plant hardiness zones 7 through 10. It requires about 1 inch of water per week, so soak the soil thoroughly.

The plants flower from midsummer through the first frost. They are not winter hardy, so must be dug up and stored in cold-winter areas. When the plants die back in fall, the corms are left in the soil in temperate climates to produce new foliage and flowers in spring. In cold-winter zones, dig them out; then store the corms in a well-ventilated basement or garage until spring.