Black ball cornflower is a striking cultivar of Centaurea cyanus, known for its deep, velvety maroon-to-almost-black blooms rather than the classic bright blue. The flowers form rounded, thistle-like “balls” of finely cut petals. Like other cornflowers, ‘Black Ball’ thrives in full sun, and attracts a wide range of pollinators, while also tolerating poor or dry soils. This cultivar is an annual but self-seeds, often returning year after year.