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How to Grow: Gladiolus
Learn about the best ways to grow great glads in your garden.
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How to Grow: Gladiolus
Gladiolus hybrids
Other Name
sword lily
Sun Requirements
full sun
Bloom Period and Seasonal Color
Summer in a wide range of colors such as white, yellow, pink, red, purple, and bi-color
Mature Height x Spread
3 to 4 feet x 12 inches
Added Benefits
deer resistant
There is no flower more stunning in an arrangement than gladiolus. They are popular curt flowers for all occasions, from weddings to funerals. Even though they are mostly know as a cut flower, gladiolus look beautiful in the flower garden as well, especially when grouped together and planted next to complimentary flowers. If you want color, gladiolus is your flower. Varieties are available in almost any color of the rainbow, with many having frilly flowers and bi-colored blooms. The sword-like leaves yield a spiky flower stalk with individual flowers that bloom from the bottom up. To keep flowers coming all summer and fall continue to plant bulbs (known as corms) into early summer.
Where, When and How to Plant
Gladiolus is not hardy in New England, so bulbs need to be dug in fall and stored or simply grown as an annual flower. Purchase bulbs (corms) from your local garden center. The largest corms will yield the best flowers. Plant bulbs in spring after all danger of frost has passed, about the time you’d plant corn, on well-drained soil. Gladiolus grows best on sandy loam soil. If you have clay soil, consider raising the beds for better water drainage. Plant the bulbs 4 times the diameter of the bulb deep. Amend the soil with compost and some bulb fertilizer in each hole. Space bulbs 6 to 10 inches apart.
Growing Tips
As gladiolus grows, tie the flower stalks to a stake or use wire cages to keep the stalk growing straight and not flopping. Keep the soil evenly moist by watering and mulching with bark mulch. For using in flower arrangements, harvest the flower stalks after the first few flowers open. In the garden, let the whole flower stalk bloom and cut it to the ground after the flowers fade.
Regional Advice and Care
Thrips insects can attack gladioli flowers. These small, white insects will feed on the flowers and leaves causing them to be streaky and discolored. Spray insecticidal soap on the plants to kill the thrips. If storing those bulbs, dip the corms for 2 minutes in hot water, dry and store to kill the thrips for next season.
Companion Planting and Design
Gladiolus are usually planted in rows to be harvested as a cut flower, but they also can be used in the perennial flower border planted with dahlias and tall zinnias to give the garden a late season flower boost. Plant gladiolus near plants that will hide their foliage once their blooms have passed. Shorter varieties grow well in containers.
Try These
‘Candyman’ has deep pink colored flowers. ‘Dream’s End’ has a bright orange flower stalk that stands 3 feet long. ‘Frizzled Coral Lace’ has ruffled, coral and salmon colored flowers. The ‘Flevo Series’ comes in many colors, such as red, yellow blue flowers, and only grows 2 feet tall reducing the need for staking.
Excerpted from my book, New England Getting Started Garden Guide.
Podcast Transcript
This South African native flower is also known as the sword lily. It’s in the iris family and gardeners have been breeding and growing it for hundreds of years. It’s the birth flower of August and said to symbolize infatuation. Have you guessed it yet? It’s the gladiolus.
I have to admit, when I say gladiolus I normally think of funeral flowers. But that’s actually a compliment to this colorful bulb. Gladiolus makes excellent cut flowers and the stems are so showy you really feel like you’re getting your money’s worth when you grow them. While most gardeners are familiar with the large and colorful flowered hybrids, there are many heirloom and species types that have smaller, more delicate stalks and are tougher plants. The ‘Nana’ gladiolus have 2 foot tall flower stalks and small, orchid-like flowers. ‘Atom’ gladiolus grows less than 3 feet tall with bright red, fringed in white, flowers. And the heirloom ‘Abyssinian Glad’ features small white flowers with a purple throat and a sweet fragrance.
Whether you’re growing one of the hundreds of hybrids or experimenting with some of these smaller species types, you grow gladiolus the same way. Glads like a well drained soil in full sun. They grow from corms planted in spring after all danger of frost has passed. Since they’re often used as a cut flower, plant in rows so you can care for them easier. Keep well watered and spray neem oil to control thrips insects that can attack the flowers. Consider staking or supporting tall varieties to keep the flower stalks straight. When about three blossoms are open on the stalk, cut it at the base and bring it indoors to let the rest of the flowers open. In fall dig and store the corms indoors.
Now for this week’s tip, in shady areas consider planting colorful foliage annuals such as coleus, perilla, and alternanthera. These add brightness to dark corners without relying on flowers.
From the Vermont Garden Journal on Vermont Public Radio
