Gladiolus produce elegant, 3-foot flower spikes with orchid-like blooms. They are spectacular in a vase and equally beautiful in perennial gardens, annual flower borders, container gardens and even vegetable gardens.
Gladiolas come in gorgeous colors, ranging from white, yellow, pink and lavender, to rose, burgundy, purple and even green. The bulbs are incredibly easy to grow. Just plant them in spring for flowers in late summer.
START WITH A BETTER BULB
It’s easy to see a difference in quality when you compare two sizes of gladiolus corms. Larger corms grow into bigger plants and produce more impressive flowers. Longfield Gardens sells only plump, 12/14 cm gladiolus corms, which outperform smaller, 10/12 corms.
SHADE AND SUN: Gladiolus will grow in full sun or partial shade.
ZONE: Gladiolas are winter hardy in zones 7-10. In cooler zones they can be grown as annuals or the corms can be dug up in the fall and stored indoors for replanting the next spring. Not sure about your growing zone? Check the USDA Hardiness zone map here.
WHEN TO PLANT: Gladiolus corms can be planted from spring through early summer, starting up to two weeks before the last spring frost.
WHERE TO PLANT GLADIOLUS
CUT FLOWER GARDENS: Gladiolus corms are inexpensive and quick to plant. They also don’t take up much room. You can grow as many as 50 stems in a 2 ft x 4 ft. area. Be sure to stagger the plantings so you have new glads opening every week from late summer through fall. The stems last for at least a week in a vase. Just pull off the bottom flowers as they fade.
FLOWER BEDS AND BORDERS: Gladiolas begin blooming in late summer when many other flowers are starting to fade. Their flower spikes stand tall among other plants, adding both color and vertical interest. Once the flowers fade, the glad’s sword-like foliage continues to be an attractive addition to the garden.
CONTAINERS: Gladiolas can hold their own in big planters with other bold tropicals such as cannas, elephant ears and coleus. In smaller containers, plant glads that are slightly shorter in height such as glaminis and peacock orchids. All will deliver a welcome, late summer surprise of color.
VEGETABLE GARDENS: As you remove early vegetable crops, such as peas, lettuce and spinach, plant some gladiola corms in the empty spaces. When it’s time to start harvesting your eggplants and tomatoes, you'll also be picking brightly colored gladiolus to adorn your dining room table.
PLANTING IS AS EASY AS 1-2-3
1. Dig a hole 3” to 4” deep.
2. Set the gladiola corm into the hole with the sprout facing up.
3. Cover the corm with soil and water as needed.
When you plant a gladiolus corm, it already contains everything it needs to produce a 3 to 4 foot flower spike with up to 20 fist-size florets. Gladiolus flowers open one by from the bottom up, so each stem will be in bloom for up to two weeks.
Planting time determines bloom time, so instead of planting all of your gladiolus corms at once, purchase enough so you can plant a handful every week from spring through early-summer. It typically takes 10 to 12 weeks from planting to flowering. Your last planting can be about 12 weeks before the first frost date in your growing zone.
Planting a couple different types of glads is another way to extend the flowering season. In addition to the full size hybrids, consider planting peacock orchids, Gladiolus muriale, as well as the hardier, dwarf gladiolas know as Gladiolus nanas or Glamini glads.
Gladiolas are easy and adaptable, but they grow best in fertile, well-drained soil. Plant the corms 3 to 4” deep and about 5” apart. Planting even a little deeper will help keep the stems upright. In a cutting garden, gladiolus can be planted in a grid pattern, 5” on center. In beds, borders and containers, they look best planted in informal groups of 7 or more bulbs.
When the flowers on a gladiolus spike start to open, the stem may get top-heavy and start to lean. For a quick fix, use slender bamboo canes to prop them up. Just slip a cane beside any stems that aren’t standing straight and use twine to secure the stem.
CARING FOR GLADIOLAS AFTER THEY BLOOM
Gladiolas are winter hardy in zones 7-10, so in these warm climates the corms can be left right in the ground. In colder zones, the corms need to be dug up in the fall and stored indoors for replanting the following spring. Another option is to treat gladiolas as annuals. Simply pull out the plants at the end of the season and plant fresh bulbs each spring..
If you want to save the corms from one year to the next, here's what to do. Cut off the spent flower stalks as soon as they finish blooming. Let the leaves continue to grow. Fertilize the plants and keep the area weeded.
After the first frost, use a garden fork or spade to lift out the entire plant, keeping the foliage attached to the corm. Let the plants dry in a well-ventilated area for a couple weeks. When the foliage has shriveled and the stems are dry, cut off the stems, leaving about an inch of stem attached to the corm.
You'll probably see little “cormels” clinging to some of the corms. If you want to try your hand at growing your own supply of gladiolus bulbs, you can start with these miniature corms, but it will take several years for them to reach blooming size. Otherwise, use your thumb to gently rub them off.
Layer the corms in dry peat moss and store them away for the winter in a cool place that is 40-50°F. Make sure they don't freeze. Next spring, simply remove any dried bits from last year’s corms and replant.