I planted 75 new gladiolus bulbs in spring. There is good leaf growth but no flower spikes on any of the plants.
Corm size, fertilization practices and pest problems can prevent flowering. Small, undersized glad corms will produce leaves but no flowers. Save larger corms to use in next year’s garden. Smaller corms can be saved and grown for two seasons to reach flowering size. Avoid high nitrogen fertilizer that encourage leaf growth and discourage flowering. If these aren’t the problem, take a closer look at the plant. Thrips, virus, and aster yellows can prevent or distort flowers. Discard diseased infested corms. You can treat thrip-infested corms with an insecticide labeled for this purpose prior to storage. For best results discard all infested plants and corms and start with new pest free corms next season.
Growing gladiolus in your garden adds a burst of color and vibrance when they bloom in summer Their sword-like foliage and showy flower spikes are a beautiful addition. However, it can be frustrating and disappointing when your gladiolus fail to bloom
There are several potential causes for gladiolus not blooming. By understanding the reasons why and implementing solutions you can get those gladioli to flower again!
1. Improper Sun Exposure
Gladiolus need full sun to thrive and bloom well. They require at least 6 hours of direct sunlight each day during the growing season. With insufficient light, the plants expend energy on foliage growth rather than developing flowers.
If your gladiolus bed or row doesn’t get enough sun, consider moving them to a new sunny location. Or, reduce shade by pruning back overhanging branches or removing competing plants. Morning sun is ideal as it dries foliage and prevents fungal diseases.
2. Overcrowding
When gladiolus are planted too close together, there is competition for nutrients, light and air circulation. This stress can inhibit blooming, cause weaker stems, or increase pest and disease problems.
Carefully dig up the corms in fall and replant them with proper spacing the following year. Give each corm 4-6 inches of space all around. Wider spacing of 8-12 inches is better for the large flowering varieties.
3. Improper Planting Depth
The corms must be planted at the proper depth below the soil surface to bloom well. If planted too shallow, they may dry out get damaged or fail to root properly. When planted too deep they can’t get enough warmth to emerge and grow vigorously.
Check the planting depth and adjust as needed. Plant large corms 5-6 inches deep. Smaller new corms should be 3-4 inches deep. Proper planting in fall is key for blooms the next summer.
4. Small or Damaged Corms
Healthy, robust corms that are at least 2 inches wide typically produce the best flower spikes. Using corms that are small, shriveled or otherwise compromised won’t give the plant the initial energy needed to establish and bloom.
When purchasing gladiolus corms, select large, blemish-free ones. Reject any that are too small, mushy, moldy or injured. And dig up and discard any diseased corms found when lifting in fall. Starting with quality corms prevents no blooms.
5. Insufficient Watering
Gladiolus have relatively high water needs, especially when blooms are forming. Soil moisture stress during growth and flowering can lead to failure to bloom or bud drop. Leaves may also appear wilted or yellowed.
Provide 1-2 inches of water per week by rainfall or irrigation during the growing season. Use a soaker hose or drip irrigation to avoid wetting foliage and limit disease. Water deeply and infrequently, rather than frequent light sprinkling.
6. Excessive Fertilizer
While gladiolus benefit from some fertilization, using too much high-nitrogen feed can result in lush foliage but no flowers. Excess nitrogen encourages leaf and stem growth at the expense of blooms.
Avoid heavy feeding with nitrogen-rich fertilizers like manure and compost. Moderate amounts of balanced fertilizer (10-10-10) applied in early spring and midsummer are sufficient. And limit lawn fertilizer near gladiolus beds, as it’s usually high in nitrogen.
7. Corm Decline
Gladiolus corms gradually decline in vigor over time. After 3-5 years, the original planted corms tend to produce poorer growth and flowering. However, they multiply each year which provides replacement corms.
To maintain blooming, dig and separate corms in fall every 2-3 years. Discard the oldest, most shriveled ones. Replant only large, healthy corms at the proper depth and spacing for abundant flowers the following summer.
8. Thrips Infestation
Tiny pests called thrips can devastate developing gladiolus flower buds. They rasp and feed on the buds, causing them to become malformed or drop off before opening. You may see silvered, spotted or streaked foliage and flowers.
Control thrips with labeled insecticides or insecticidal soap sprays starting when you see the first signs of damage. Remove and destroy all foliage and stems after blooming finishes to eliminate overwintering sites for thrips.
9. Insufficient Winter Storage
In northern zones where winters get quite cold, the corms must be dug and stored over winter. If left in the ground, freezing temperatures will kill them. Storing them in unsuitable conditions also causes loss of viability.
After the leaves die back in fall, carefully dig up the corms. brush off soil and remove the old, dried corms. Place the rest in breathable mesh bags or trays. Store in a cool (40-50°F), dark place for winter. Keep them slightly moist but not soggy or moldy.
With the right growing conditions and care, your gladiolus will reward you with their beautiful blooms year after year. Pay close attention to proper planting, sunlight, water, fertilization and pest control. And provide suitable winter storage where needed. By identifying and correcting any issues, you can get those gladioli flowering again!
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Why are my Gladioli not flowering?
Why is my Gladiolus not blooming?
If the area has become overgrown or shaded by a tree or hedge, there will be no blooms on gladiolus since the plant needs full sun to bloom. Additionally, the planting site may become too compacted over time for the slender stems and leaves to push through. Lifting and re-cultivating the soil annually will ensure this doesn’t occur.
How long does it take a Gladiolus to bloom?
You can get gladioli to flower faster than 10 weeks. ‘To do this, you need to plant corms deep in seed trays in a single layer, keep the soil moist, then put them in a warm greenhouse or propagator. Once they have rooted and shooted, transfer them outside in warm soil. Why aren’t my gladiolus blooming?
Are Gladiolus winter hardy?
Here’s how it works. Gladiolus plants are lovely spikes of color that grace the landscape in summer. They are not very winter hardy and many northern gardeners may experience the frustration of their gladiolus not blooming after the cold season.
Are gladiolus corms too old?
They may be too old : gladiolus corms do produce new flowers year after year, but will eventually run out of steam over time. For this reason, it’s wise to keep planting new corms year on year. The corms are too small: by next year, with some care and feeding, the corms should produce good growth and blooms.