Troubleshooting
Garden Gladiolus problems — and how to fix them
Garden Gladiolus (Gladiolus ×hortulanus) is generally forgiving once you match its basics, but a few issues come up again and again. Here is what each one looks like, why it happens, and the fix.
Gladiolus thrips (Taeniothrips simplex)
The most damaging pest — minute insects pierce cells causing silvery streaking on leaves and distorted, discoloured, or unopened flowers. Inspect and treat corms before storage with an insecticidal dust; use systemic insecticide on severely infested growing plants.
Fusarium corm rot
A soil-borne fungal disease producing yellowing foliage from the base and a dry brown rot on corms. Avoid replanting gladioli in the same bed for at least 4 years; destroy (do not compost) infected corms; treat healthy corms with a fungicidal dip before storage.
Botrytis blight
Grey mould (Botrytis cinerea) causes water-soaked spots on leaves and flowers in wet, humid conditions. Improve air circulation by correct spacing; remove and bin affected material promptly; apply a copper-based fungicide if necessary.
Prevent garden gladiolus problems before they start
Most garden gladiolus issues are care-mismatch, not bad luck. Dial in the basics:
Looking for garden gladiolus in general rather than its problems? Read the full garden gladiolus care guide — light, water, soil and feeding.
Garden Gladiolus problems — FAQ
Why is my garden gladiolus gladiolus thrips (taeniothrips simplex)?
The most damaging pest — minute insects pierce cells causing silvery streaking on leaves and distorted, discoloured, or unopened flowers. Inspect and treat corms before storage with an insecticidal dust; use systemic insecticide on severely infested growing plants.
Why is my garden gladiolus fusarium corm rot?
A soil-borne fungal disease producing yellowing foliage from the base and a dry brown rot on corms. Avoid replanting gladioli in the same bed for at least 4 years; destroy (do not compost) infected corms; treat healthy corms with a fungicidal dip before storage.
Why is my garden gladiolus botrytis blight?
Grey mould (Botrytis cinerea) causes water-soaked spots on leaves and flowers in wet, humid conditions. Improve air circulation by correct spacing; remove and bin affected material promptly; apply a copper-based fungicide if necessary.