Scabious knapweed
Centaurea scabiosa · Asteraceae
The gardener's calendar
Ideal time to plant scabious knapweed: set it out when the soil is neither frozen nor waterlogged, and water generously as it establishes.
ID card
- Foliage
- Deciduous
- Flowering
- June to September
- Adult size
- 60 to 100 cm height
- Growth
- Moderate
- Hardiness
- Very hardy (down to -20°C)
- Origin
- Central and Mediterranean Europe
- Soil type
- Well-drained, chalky, poor to medium
Care
Watering
Water moderately during the growing season, once or twice a week depending on conditions. Once established, this plant tolerates drought well and only needs water during extreme heat. Avoid excess moisture which promotes root rot.
Light Exposure
Place the field scabious in full sun for optimal and abundant flowering. It tolerates partial shade but will flower less abundantly. Good air circulation helps prevent fungal diseases.
Soil Preparation
Prepare well-drained soil, slightly chalky or neutral, poor to medium in organic matter. Adding sand or gravel improves drainage. This plant prefers dry terrain and cannot tolerate compact or continuously wet soil.
Pruning and Cutting
Remove spent flowers regularly to extend the flowering period. In late autumn or early spring, cut stems back to 10-15 cm to encourage a compact, bushy habit. You can harvest flowers in tight bud stage for flower arrangements.
Fertilization
This hardy plant requires very little fertilizer. A light application of compost in early spring is more than enough. Avoid excessive nitrogen fertilizers which promote vegetation at the expense of flowering.
Diseases and Pests
Field scabious is generally very resistant. Watch for powdery mildew in humid weather: improve air circulation or spray an appropriate treatment if necessary. Aphids may occasionally affect it; a spray of water is often sufficient.
Did you know?
Field scabious gets its scientific name 'scabiosa' because it was once used in medieval medicine to treat scabies. In the Middle Ages, its magnificent purple flowers were long called the 'Flower of the Holy Cross' and planted near churches for their supposedly protective virtues.
Where to buy it
Plant in spring or early autumn, avoiding spells of intense heat. Pick a plant with healthy foliage and roots that are not exposed. Best time: March, April, May, September.
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Tips generated and checked by Viridia — adapt them to your local climate.