How to Grow Gladioli
Gladiolus
When to Start
Plant directly outdoors once soil temperature reaches 10°C. No seed starting needed — grow from bulbs, tubers, or sets.
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Growth Stages
Approximate days from start
Care Essentials
- Balanced feed at planting. High-potash feed when flower spikes appear.
- Plant corms every 2 weeks from March to May for a succession of flowers. Stake tall varieties.
Companion Planting
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Growing Conditions
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- Direct sow
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- First harvest
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Spacing & Planting
| Plant spacing | 15 cm |
| Row spacing | 30 cm |
| Sow depth | 10 cm |
| Mature height | 120 cm |
| Mature spread | 15 cm |
Plant corms 10-15cm deep. Stagger planting every 2 weeks for extended flowering. Stake tall varieties.
Care Guide
- Feeding
- Balanced feed at planting. High-potash feed when flower spikes appear.
- Watch for
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- Thrips
- Grey mould
- Gladiolus corm rot
- Slugs
Pests & Diseases
Pest Gladiolus Thrips
Identification: Silvery streaking and speckling on leaves and flowers; tiny slender brown insects visible on petals. Severe infestations cause flowers to fail to open
- Spray with fatty acid-based insecticide when damage first appears
- Soak corms in warm water (43°C for 30 minutes) before planting to kill overwintering thrips
- Spray with a contact insecticide containing deltamethrin or lambda-cyhalothrin
Pest Slugs and Snails
Identification: Young shoots eaten or with irregular holes; slime trails around plants
- Apply organic slug pellets (ferric phosphate) around emerging shoots
- Use beer traps or copper tape barriers
- Encourage hedgehogs, frogs and ground beetles
- Ferric phosphate-based pellets
Pest Aphids
Identification: Clusters of small green insects on leaves and developing flower spikes, causing distorted growth
- Blast off with a strong jet of water
- Spray with fatty acid-based insecticide
- Encourage ladybirds and hoverflies
- Spray with a contact insecticide if infestation is severe
Disease Gladiolus Corm Rot (Fusarium) Fusarium oxysporum f. sp. gladioli
Symptoms: Yellowing and wilting foliage; brown, sunken, dry rot on corms, often with pinkish fungal growth
Treatment: Destroy affected corms. Do not replant gladioli in the same spot for at least 4 years
Prevention: Inspect corms carefully before planting and discard any showing signs of rot. Ensure good drainage and cure corms thoroughly before storage
Disease Grey Mould (Botrytis) Botrytis gladiolorum
Symptoms: Brown spots on leaves and flowers that develop fuzzy grey mould in damp conditions; corms may rot in storage
Treatment: Remove and destroy affected parts. Improve air circulation around plants
Prevention: Space plants well, avoid overhead watering, and ensure corms are thoroughly dried before winter storage
Disease Gladiolus Scab and Neck Rot Burkholderia gladioli pv. gladioli
Symptoms: Round, raised, dark lesions on corms with a shiny, varnished appearance; neck rot causes collapse at the base of the stem
Treatment: Destroy affected corms. Do not replant in contaminated soil
Prevention: Inspect corms before planting, ensure good drainage, and rotate planting sites
Growing Conditions
| Min. soil temperature | 10°C |
| Germination temperature | 15–20°C |
| Photoperiod sensitivity | day neutral |
Frequently Asked Questions
- How far apart should I plant Gladioli?
- Plant Gladioli 15cm apart with 30cm between rows.
- When does Gladioli flower?
- Gladioli typically flowers approximately 90 days after transplanting.
- Is Gladioli frost hardy?
- Gladioli is classified as Half Hardy.
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