Pest identification
What's eating my dazzler cosmos?
Aphids
Signs: Clusters on shoot tips and flower stems; honeydew, sooty mould, and distorted buds on the vivid flowers.
Control: Spray with insecticidal soap or neem oil; introduce beneficial insects; water jet to dislodge colonies.
Thrips
Signs: Silvery-white flecking and streaking on petals; flowers may be deformed and fail to open properly.
Control: Remove damaged blooms; apply spinosad or insecticidal soap; avoid excess nitrogen that promotes lush growth.
Slugs and snails
Signs: Young stems cut at or below soil level; seedlings can be lost entirely overnight.
Control: Delay outdoor transplanting until plants are sturdy; use iron phosphate pellets and grit mulch.
Deer
Signs: Flower heads and upper stems browsed, leaving bare stalks, particularly on plants in exposed borders.
Control: Apply deer repellent; fence the growing area; or position containers on raised surfaces.
Keep dazzler cosmos pest-free
Healthy plants resist pests best. Get the basics right:
Dazzler cosmos pests — FAQ
What is eating my dazzler cosmos?
Dazzler cosmos (Cosmos bipinnatus 'Dazzler') shares the pest profile of all C. bipinnatus: aphids are the most frequent problem, followed by thrips distorting the bright red blooms. Slugs attack seedlings and young plants. Deer readily browse cosmos in open gardens. The plant is otherwise tough and few pests cause serious long-term damage.
How do I get rid of aphids on dazzler cosmos?
Clusters on shoot tips and flower stems; honeydew, sooty mould, and distorted buds on the vivid flowers. Spray with insecticidal soap or neem oil; introduce beneficial insects; water jet to dislodge colonies.
How do I get rid of thrips on dazzler cosmos?
Silvery-white flecking and streaking on petals; flowers may be deformed and fail to open properly. Remove damaged blooms; apply spinosad or insecticidal soap; avoid excess nitrogen that promotes lush growth.
How do I get rid of slugs and snails on dazzler cosmos?
Young stems cut at or below soil level; seedlings can be lost entirely overnight. Delay outdoor transplanting until plants are sturdy; use iron phosphate pellets and grit mulch.
How do I get rid of deer on dazzler cosmos?
Flower heads and upper stems browsed, leaving bare stalks, particularly on plants in exposed borders. Apply deer repellent; fence the growing area; or position containers on raised surfaces.