A profusion of cut petals in burgundy to almost black makes 'Black Swan' a must-have flower for cottage gardens, at home among annual larkspurs and early summer bloomers. A similar variety was introduced in 1922, with flowers "of a dark heliotrope-violet, inclining to black-violet, and beautifully feathered." Stake or underpin with twiggy brush for support. Remove after flowering, leaving a few to self sow.