Centaurea cyanus 'Black Ball' / Black Cornflower / Seeds

(Code: TH_024)
(19 Item(s) In Stock)
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Centaurea cyanus 'Black Ball' / Black Cornflower / Seeds

A great variation of the blue Cornflower.  This black Cornflower has rich deep mauve double flowers, showing in clusters on strong wiry stems from June right through to the first frost.  Growing to about 75cm in height, these look great in a border, grown together in groups. Contrasts well with Verbena, Monarda and Knautia all available from our shop.  Also makes a very good cut flower.

Centaurea likes full sun and a rich well drained soil. Regular feeding and water will increase the flowering.


Pack of approx 100 seeds.  Sow in the autumn/winter for an early start or sow directly in the soil in the spring.  Sowing instructions and a colour photo are printed on the packet.

See how your seeds are packed.

Hardiness Hardy annual (RHS Hardiness H7)
Flowers June to the first frost
Height 70 - 90cm
Spread 20 - 40cm
Conditions  Grow in full sun and well drained soil

Sow in spring directly in the soil 1-2cm deep.  Or start earlier in autumn/winter in seed trays, with a covering of compost and keep at 15-20C.  Germination takes 10-14 days.  Protect young seedlings in a cold frame or greenhouse over winter and plant out in the spring.


Water regularly until young plants are established. Plants may need staking in more exposed gardens. Deadhead plants to prolong flowering.  Remove plants after they have finished flowering and sow more seed the following year.  Leave some seedheads on the plant if you want the plants to self-sow however, plants in following years may flower indifferent colours.