Centaurea cyanus 'Black Ball'

Centaurea cyanus 'Black Ball' is a very fine tall variety, a double flowered cultivar of the blue wildflower form, with lance shaped, long and graceful leaves. The upper half of the plant has multiple stems which produce many flowers from early summer until frost.
A favourite annual flower and cottage garden staple, a single cornflower looks like a burst of fireworks. The flowers appear from early to late summer

The Ball series, also known as the Boy series, feature double flowered blooms on tall stems for garden or cutting, are available in many colours including Black, Blue, Pink, Red and White.
These beauties grow well as border plants and are wonderful in a cutting garden; they look fabulous clustered among other contrasting flowers such as roses. “Black ball” flowers are a lovely rich dark-chocolate hue, almost black on cloudy days!

Sowing
Sow in August to September for early summer flowering the next year or sow directly where they are to flower in March to April

Sowing Direct :
Sow thinly, 3mm (1/8in) deep in drills 30cm (12in) apart in well-cultivated soil which has been raked to a fine tilth. Water ground regularly, especially in dry periods.
When large enough to handle, thin out seedlings to 15cm (6in) apart

Sowing Indoors:
Sow in pots or trays of moist seed compost and cover with a very fine sprinkling of compost or vermiculite. After sowing, do not exclude light as this helps germination. Keep at 15-20°C (59-68°F). Keep the surface of the compost moist but not waterlogged. Germination will usually take 14-21 days.
When they are large enough to handle, transplant the seedlings into 7cm (3in) pots or trays. Overwinter plants in cool, light, frost-free conditions before planting out the following spring, or grow on as greenhouse pot plants.

Cultivation:
This fully hardy plant requires a sunny site, growing in most well-drained soil types, even poor soil. Do not over fertilise because this will lead to excessive leaf growth at the expense of blossoms. Cornflowers bloom more when crowded.
The wiry plants may need some discreet support, and deadheading helps to prolong the flowering season.

Plant Uses:
Flowers Borders and Beds, Patio/Container Plants, Cut Flower, Attracts Butterflies, Drought Tolerant, Everlasting (use for drying and pressing, Cornflowers retain their colours when dried)

Other Uses:
Cornflowers are prized historically for their blue pigment. Cornflowers are often used as an ingredient in tea and is famous in the Lady Grey blend of Twinings.

Nomenclature:
Once upon a time anything that grew and bloomed in a grain field was considered a 'cornflower.' As time passed, that moniker stuck to Centaurea cyanus in particular, all the other flowers left to find their own names.
Bachelor's-buttons, as you might suspect from the Latin genus and species, have a bit of folklore under its belt. Cyanus was a youth in Greek legend who worshipped Chloris (or Flora), and spent every waking hour gathering flowers for her altar. (Today we call that a stalker.) When he died, the goddess gave his name to the plant, though some believed she turned him into the plant.
Centaurea comes to us from the Centaur Chiron, who cured a festering wound that was made with an arrow dipped in the Hydra's blood. The wound was cured by covering it with the flowers of this plant, which now bears his name as its genus name. This also gave the plant its reputation for great healing properties.

Other common names:
Ragged sailor, Witches' bells, Happy skies, Haw dods, Hurtsickle, Cornbottle, Corn centaury, French pink, Brushes, Bunk, Corn binks, Blue tops, Bluets, Break-your-spectacles, Blue bow, Blue poppy, Blue sailors, Blue blaw, Blue bonnets, Bluebottle, Barbeau, Blaver, Blawort.