GardenWizzPlant Care Card

Cornflower

Centaurea cyanus · Annual

Hardiness
H6 Hardy — very cold winter (to −15 to −20°C)
Position
Full sun
Height × Spread
20–100 cm × 10–50 cm
Soil
well-drained soil; loam, sand; acid, alkaline, neutral pH; adaptable to poor soils
Flowering
June–September
Toxicity
No specific toxicity is listed by the RHS. This is not a guarantee of safety — check with a vet or the ASPCA before pets or children eat any plant.

The Gardening Year

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F
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A
M
J
J
A
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🌱 Sow
🪴 Plant out
🌸 In flower

Watch out for

Powdery mildew: Ensure good air circulation and avoid overhead watering; remove severely affected foliage.

Slugs and snails: Use physical barriers like copper tape or organic pellets to protect vulnerable young plants.

Vine weevil: Check potted seedlings for grubs and apply biological nematodes or systemic controls if found.

Aphids: Encourage natural predators like ladybirds or blast off with a strong jet of water.

Root rot: Plant in well-drained soil and avoid overwatering to prevent fungal attack on roots.

Full guide: gardenwizz.com/plants/cornflower © GardenWizz — UK gardening encyclopedia