How to Grow Black Knight
Scabiosa atropurpurea
Scabiosa atropurpurea 'Black Knight' offers striking dark purple blooms that attract pollinators to your garden. This easy-to-grow annual provides a long season of color, making it an excellent choice for borders or cutting gardens where its delicate flowers stand out.
📷 Wikimedia CommonsStarting Black Knight: indoors or direct sow?
🌾 Sow directly in the garden — Black Knight is not usually started indoors.
Direct sow seeds outdoors after the soil has warmed in spring or early fall, as this plant prefers cooler temperatures and is not suited for transplanting seedlings indoors.
Soil, care & harvest
Prepare well-draining soil with a neutral pH around 6.0 to 7.0. Although the database lists this as a warm-season crop, Scabiosa is actually a cool-season plant that thrives in cooler weather. Sow seeds directly outdoors 2 to 4 weeks before your last expected frost date. Plant them at a depth of about one-quarter inch and expect germination within 7 to 14 days.
Space plants 18 to 24 inches apart to ensure good air circulation. While they do not require staking, provide support if growing in very windy locations. Water regularly to keep the soil evenly moist but avoid wetting the foliage to reduce disease risk. Apply a light layer of mulch to retain moisture and feed with balanced fertilizer every few weeks during active growth.
Watch for aphids, slugs, and powdery mildew; treat infestations early with insecticidal soap or by hand-picking pests. Prevent fungal issues by ensuring good airflow and avoiding overhead watering. Harvest flower heads for drying or cutting when the blooms are fully open but before they begin to fade. This variety typically takes 90 to 100 days from sowing to harvest.
When to Plant Black Knight
Planting windows vary by USDA hardiness zone. Look up yours by ZIP code.
| Zone | Start Indoors | Direct Sow | Harvest |
|---|---|---|---|
| Zone 1 | May – June | July – September | — |
| Zone 2 | April – May | June – August | — |
| Zone 3 | April – May | June – August | — |
| Zone 4 | March – April | June – July | — |
| Zone 5 | March – April | May – July | — |
| Zone 6 | March – April | May – July | — |
| Zone 7 | February – March | April – June | — |
| Zone 8 | February – March | April – June | — |
| Zone 9 | January – February | March – May | — |
| Zone 10 | January | February – April | — |
| Zone 11 | January | January – March | — |
| Zone 12 | January | January – March | — |
| Zone 13 | January | January – March | — |
Companion Plants for Black Knight
✓ Good companions
Deters ants and aphids while attracting pollinators
Attract beneficial insects and provide structural contrast
Similar growing conditions and repels moths and flies
Repel aphids and other pests while attracting beneficial insects
Act as trap crop for aphids and cucumber beetles
Similar care requirements and attracts hummingbirds and butterflies
Ground cover that attracts beneficial insects and predatory wasps
Attract beneficial insects and provide complementary colors
✗ Keep away from
Produces juglone toxin that inhibits growth of many flowering plants
Releases allelopathic compounds that suppress nearby plant growth
Inhibits growth of most garden plants through allelopathic effects
