Image Credit:
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Botanical Name
Gladiolus spp.
Grown as
Toxicity
Sun Exposure
Water Needs
Height
Spread
Soil pH
Bloom Time
Resilience
Plant Type
Planting
For the best blooms, plant glads in full sun (6 to 8 hours of sunlight per day) in well-draining soil that’s moderately fertile. They will not do well in heavy, soggy soil. Mix compost (humus) into your soil to improve consistency and fertility.
When to Plant Gladiolus
- Start planting gladiolus corms in the spring once the danger of frost has passed and the soil has warmed to at least 55°F (about 13°C). See your local frost dates here.
- From your last frost date to early summer, plant another round of corms every 10 days or so. This will result in continuous blooms through early fall!
- Depending on the variety, it takes between 60 and 90 days from the time glads are planted for the corms to root, grow, and bloom.
How to Plant Gladiolus
- Ready your garden by using a garden fork or tiller to loosen the soil to about 12 to 15 inches deep. After loosening the soil, mix in a 2- to 4-inch layer of compost or aged manure.
- To ensure large-sized blooms, plant corms that are 1-1/4 inch or larger in diameter.
- Set the corm in the hole about 4 inches deep with the pointed end facing up. Cover with soil and press firmly.
- Space the corms 6 to 8 inches apart.
- If you grow gladioli primarily for cut flowers, plant them in rows. It’s easier to tend the plants and to harvest the flowers this way.
- If you plant glads with other flowers in borders or annual beds, plant the corms in groups of seven or more for the best effect.
- Water the corms thoroughly at planting.
- If you’re planting tall varieties, be sure to stake them at planting time. Be careful not to damage the corms with the stakes.
Growing
How to Grow Gladiolus
- Put a 2- to 4-inch layer of mulch around your gladioli to keep your soil moist and help prevent weeds.
- If you get less than 1 inch of rain a week, water your plants regularly throughout the summer. Otherwise, water them moderately when they are growing to keep the soil moist.
- Remove the faded/dead flowers to ensure continuous blooms. Once all the flowers on a stalk are gone, cut the stalk off at about 2 to 3 inches above the soil.
- Be sure to leave the plant intact so it can mature and grow the corms for the next season.
Winter Protection for Gladiolus
- If you live in USDA Hardiness Zone 8 or warmer, put down a layer of hay or straw for winter protection. Gladiolus can remain in the ground through winter, provided a hard freeze (28°F or colder) isn’t common in your area.
- In colder regions (Zone 7 or colder), dig up gladioli corms once the foliage has faded after the first fall frost. A light frost will kill the foliage but not the rest of the plant. Be sure to dig up the gladiolus corms before a hard freeze (28°F), or the plants could be fatally damaged.
- All that said, many gardeners who live in the “border” Zones 6 and 7 have tried leaving glads in the ground and found that they survived; this is a judgment call based on your microclimate, your variety of gladiolus, and climate shifts.
Digging Up and Storing Gladioli Corms
To dig up the gladioli corms for winter storage, follow these tips:
- Use a spade and dig up the entire plant, grasping the top to pull it out of the soil. Avoid bruising or injuring corms while digging. Shake off all loose soil (do not wash them off) and discard damaged corms. Cut the stalk down to 1 to 2 inches above the corm. Save the small cormels separately if you so desire. These will bloom in 2 to 3 years if you replant them each spring.
- Allow the corms to dry in the sun for 1 or 2 days if the weather agrees. Sift out excess soil and place corms in wooden flats or trays. Cure in a warm and airy location for 2 to 3 weeks. Remove and throw away the oldest bottom corms (from the base of the new ones).
- Don’t remove the husks on the corms.
- Dust the corms with a fungicide (“bulb dust”) to avoid disease problems. Place dust and bulbs in a paper bag and shake vigorously.
- Store the corms in paper or cloth bags, pantyhose, or old onion sacks. Stack or hang the containers, so air can move among them. Store the corms at 35° to 45°F (2° to 7°C) in low humidity. A cool basement is quite suitable. Do not allow corms to freeze.
- Replant these corms in the spring for another year of beautiful blooms.
Harvesting
To cut glads for bouquets, follow these tips:
- Cut the flower stalks early in the morning or at night, not during the heat of the day.
- Use a sharp knife and bring a bucket of lukewarm water to the flower bed; cut diagonally through the stalks and place in the bucket.
- Cut stalks with only one or two open flowers. The rest of the buds will open after you put them in a vase. Leave at least four leaves on the plant in the ground if you want to reuse the corms.
- Place the bucket with the flowers in a cool dark place for a few hours before arranging them in a vase.
- Remove lower fading flowers and cut about 1 inch off the bottom of each flower stalk every few days.
Types
Gladioli come in a variety of sizes and colors, with the most popular being part of the following hybrid groups:
- Grandiflora Hybrids: These are the classic gladioli that produce a plentiful amount of large (5- to 6-inch) blooms in a range of colors. The plants produce flower stalks that reach up to 4 feet in height and can be winter hardy to Zone 7.
- Dwarf Grandiflora Hybrids: These miniature glads are an excellent choice for containers and cutting gardens, as their flowers are about half the size of Grandifloras, and their shorter stalks don’t typically require staking. They are also winter hardy to Zone 7. Glamini gladioli are included in this group; they are pest-resistant and will bloom in full sun or partial shade.
- Nanus Hybrids: Hardy to Zone 5, these smaller gladioli look a lot like Grandifloras, but do not produce as many flowers. They tend to grow no larger than about 2 feet in height, which makes them perfect for containers or small spaces.
Some specific gladiolus varieties of note include:
- ‘Black Star’ has deep purple-red blooms.
- ‘Candyman’ is known for its beautiful, deep pink flowers.
- ‘Costa’ sports ruffled flowers in blue-purple.
- ‘Dream’s End’ makes a good background plant because its flower spike is up to 3 feet tall (and it has pretty light orange flowers with large yellow centers).
- ‘Fun Time’ has yellow flowers edged with red.
- ‘Green Time’ is grown for its unusual lime-green flowers.
- ‘Prins Claus’ has white flowers with splashes of pink on its petals.
- ‘Priscilla’ produces off-white flowers with a yellow center and a pink edge.
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Comments
what are the buds that appear after the flower drops ?
The buds that appear after the flower drops of are little seed pods if you leave them on there wait until they turn brown then take them off. In Feb plant the seeds in side and wait until they are a few inches tall and there is no danger of frost then plant out side. They will take 2-3 years before they will flower.
I pulled up some glad bulbs that had been in the ground for several years. Some bloomed, some did not. Some of the bulbs have small white "attachments" on the bulbs. Are these new bulbs or a problem. How do I handle them? I want to transplant the bulbs. Thanks,CLaire
New gladiolus corms form immediately above the
old corm. You may see small corms called cormels form around the base of the new corm. Follow our instructions on this page for digging up the glads.
We moved to Costa Rica, the glads are big and beautiful, can I leave them in year round or should I dig them up after they bloom, also do they bloom more than once ?
I live in zone 6 and wandered if I have to pull my Glads. They are planted on the south side,against the home, and in full sun.
According to the U.S. Department of Agriculture, you do want to lift gladiolus in zones 7 and below. This is our recommendation, too. However, we've had readers in zones 7 and 6 who did not lift them and found that their glads returned and bloomed! It really depends on how much insulating snow cover they get and how warm the winter is. (This year, our prediction is colder-than-normal.) If you don't lift them, be sure to use lots of fluffy mulch such as straw, hay, oak leaves, etc.
After moving into our new home and working in my garden, I discovered a group of glads suffering to grow in a very shady area under a big tree. They had plenty of green but struggled to bloom (just got some bud-looking flowers on them.) I dug them up and want to replant them, but it is July; we are in zone 10 (so Cal.) I have prepared a bed for them, but don't know if I need to store them like in other zones or can I plant them? Store them? Please advise and thanks in advance. Donna
Plant the glads now. In a zone 10 garden you don't need to dig and store the corms in the fall. They will come up every year.
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Gladiolus are late bloomers--often September. Are the stalks thick when you run your hands up them; if so, that a good sign. Are they getting lots of sun and warmth? Is the soil nice and light and not too compact or heavy? Do you see insect damage? There are some diseases that would cause glads not to bloom. It always helps to apply fungicidal sprays during the summer to protect your glads; speak to your garden store.