Glads make every garden bed and every table vase look full! For a striking flower show and stunning cut flowers, grow gladiolus. This spring-planted corm (bulb), quickly produces flower spikes in a variety of colors that pop. This makes them a first choice for tucking into young perennial flower gardens that could use some added color while they reach maturity. Glads also make excellent cut flowers, both grouped in a vase or mixed with other flowers in arrangements.
Gladiolus seeds appear as small, flat brown discs, measuring up to 2 millimeters in size. If you examine them closely, you can actually see the embryo through the seed coat. A single seed pod typically contains between 180-200 seeds.
Identifying Gladiolus Seed Pods
- Pods form after flowers finish blooming
- Initially green, turning brown when mature
- Small and unassuming in appearance
- Take about 35-40 days to fully ripen
- Show cracks when ready for harvest
- Turn from green to yellow to brown when mature
Collecting the Seeds
To successfully collect gladiolus seeds:
- Wait for pods to turn brown and start cracking
- Remove pods before they split open and drop seeds
- Crack pods open over a bowl to catch seeds
- Store seeds in paper envelope
- Keep in cool, dark place until spring planting
Growing from Seeds vs Other Methods
While growing from seeds is possible, most gardeners prefer propagating gladiolus through:
- Bulbs (fastest blooming)
- Bulblets/cormels (bloom next season)
- Division of mature corms
Seeds take several years to produce flowers and may not grow true to the parent plant. However, seed propagation can be exciting for:
- Experimental gardeners
- Those interested in developing new varieties
- Breeders working on hybrid creation
Starting Seeds Indoors
For best results when growing from seed
- Start in February in greenhouse conditions
- Soak seeds in growth solution for 2-3 hours before planting
- Use mix of 2 parts humus to 1 part sand
- Plant seeds shallowly
- Keep soil consistently moist
- Provide bright light
- Transplant outdoors after frost danger passes
Care Tips for Seedlings
Young gladiolus plants need:
- Regular deep watering (1-1.5 buckets per square meter)
- Frequent but gentle soil loosening
- Mulching to retain moisture
- Regular weeding
- Phosphorus and potassium fertilizers
- Protection from frost
Remember – if you want flowers sooner, starting with bulbs or corms is your best bet But if you’re curious about seed propagation, why not try growing a few from seed alongside your regular bulb plantings? You might end up with an exciting new variety!
How To Plant Gladiolus
Light: Gladiolus grow and flower best in full sun. Gladiolus corms will flower in part shade, but the colors will not be as vivid as when planted in full sun, and the plant wont grow quite as well.
Soil: Gladiolus like well-drained, sandy loam soil. The corms will rot if the soil is too heavy and wet. If you have clay soil, grow in raised beds and loosen the soil to 12 inches deep before planting.
Spacing: Space gladiolus corms 6 to 10 inches apart in the garden and plant corms 2 to 6 inches deep depending upon the size of the corm (plant bigger corms deeper).
Planting: Plant gladiolus corms in spring 2 weeks before your last expected frost date. To enjoy flowers all summer, plant your Glads every 2 weeks until early July. This will stagger the plantings and flowering times. You can also extend the flower season by growing early, mid and late-season Gladiolus varieties.
How To Care For Gladiolus Throughout the Season
Growth Habit: Gladiolus have narrow, sword-like leaves and tall flower stalks. The flower stalks can grow 2 to 4 feet tall while only spreading 1 foot wide.
Staking: Gladiolus flower stalks need to be staked, caged or supported so they dont flop over, or become deformed and curved due to summer storms. Soon after planting, push flower stakes into the ground or add supports around the corm. Do this early so as not to damage the flower. As soon as the flower stalk forms, tie it loosely to a stake with a soft material, or use flower rings to support it. Remove the stakes after the flower is harvested or fades.
Planting gladiolus in groups in the garden or next to tall bushy plants is another way to keep them growing upright without producing crooked flower stalks.
Watering: Keep gladiolus plants well watered with at least 1 inch of water a week. This amount may have to increase during periods of drought or if youre growing in raised beds.
Fertilizing: Add compost to the soil before planting gladiolus. Add an organic, water-soluble fertilizer when the plants are 10 inches tall, and again when the flowers start to show color.
Trimming & Pruning: Gladiolus are either grown as a cut flower for indoor arrangements, or as an annual flower in the garden. They dont require trimming or pruning.
The flower stalk is harvested in the morning for flower arrangements when the lower 3 blossoms on the stalks begin to open. Leave at least 4 leaves on the plant to rejuvenate the corms if you plan on saving them for next year.
In the garden, deadhead the flower stalk after the flowers fade. This will also prevent the flowers from setting seed and self sowing throughout your beds. Although these seedlings will eventually get large enough to flower, it will take years and the seedlings can become weedy.
Mulching: To preserve soil moisture, mulch plants once they emerge from the soil with a 2 to 3 inchthick layer of straw or bark mulch. Gladiolus dont compete well with weeds. If the area where youd like to plant is weedy, weed before applying the mulch. The mulch should help with weed control as well.
How to Harvest Gladiolus Seedsl
FAQ
How long does it take to grow gladiolus from seed?
Should you let gladiolus go to seed?
If you let the stalks go to seed, yes, they will self seed and you’ll have lots of little babies in the area. The little fence is a huge help to keep them upright.
Does gladioli self-seed?
Gladioli species can be grown from seed. You’ll find perennial plantings can self-seed. Sow specialist species in spring in a cool greenhouse.