Gladiolus are one of the most dramatic yet sophisticated summer cut flowers. They take center stage when placed in a large vase, engaging an entire room with orchid-like blooms opening along sword-like stems. They’re available in many gorgeous colors, some also have fringed or ruffled edges. You can buy stems from grocery stores as a mid-summer treat, but you’ll be even more delighted if you’ve grown your own. Gladiolus are incredibly easy to grow, and if you stagger plantings every two weeks from early May to July, you’ll enjoy a succession of beautiful blooms from summer into fall.
Gladiolus corms are similar to bulbs, and are planted in the spring when all danger of frosted has past. If you desire armloads of cut flowers, plant gladiolus corms in rows in rich well-draining soils. Select a place that receives at least six hours of full sun, that is also protected from wind as gladiolus can grow from 60 – 150 cm (2-5’) tall. Dig a trench 6-8” deep, mixing in a bulb boosting fertilizer into the bottom of the row before setting out corms. Set corms in clusters with pointed tips up, 10 cm (4”) deep and 10 cm (4”) apart, and cover with soil. Plant corms deeply and close together so that they can help support themselves.
Staking gladiolus ensures straight stems.
Once planted, water the corms, thoroughly soaking the ground. Water regularly throughout the growing season, especially during hot and dry conditions. A good soaking once or twice a week is better than a daily light watering. The time from planting to blooming averages about 10-12 weeks, depending upon weather conditions. Gladiolus are in bloom for a short period, 1-2 weeks, so for continual summer blooms we suggest planting 8-16 corms every two weeks.
Gladiolus also grow well in containers and borders. Plant them in groupings of 5 to 8 corms or more for the best visual impact. Make sure your containers have drainage holes, as gladiolus like other bulbs enjoy well-draining soils. Pair gladiolus with lilies, dahlias, crocosmia or among perennials for a colorful summer showcase.
Gladiolus bloom from the bottom up, so when the lower blooms begin to open it’s time to gather a bouquet. The best time to cut flowers is in the morning or evening. You’ll need a sharp knife or florist’s shears and a bucket of lukewarm water. Cut diagonally through the stalk leaving at least four leaves on the remaining in-ground stem. These leaves nourish and rejuvenate the corm for the next season’s bloom. Place cut stems immediately into the bucket of water. Set the bucket in a cool, dark place for a few hours, allowing the blooms to harden off before arranging them in a vase. As flowers fade, simply remove the blossoms and trim stems to keep a fresh appearance.
If you’re enjoying gladiolus outside, wait until all the flowers have opened, withered, and dropped before cutting the stems. Leave the remaining green leaves to nourish the corms.
Gladiolus are tender bulbs for most growing regions across Canada. You’ll want to lift them for winter storage from the ground before the first hard frost arrives in your area. If you’re growing gladiolus in containers, just move the entire pot into the garage or storage shed where it won’t freeze, and your gladiolus will be ready to flower again next year.