The Bighead Knapweed is a perennial herb that is native to Eastern Europe. It was introduced to North America and the UK in the early 19th century and is still widely used in the horticultural trade as cut/dried flowers, seeds, and plants.
The Bighead Knapweed is grass with thread-like yellow, spherical flower heads 1 to 3 inches in diameter and grow individually on the stems. The plant grows on solid roots and can reach a height of one and a half meters.
It features a beautiful, showy yellow bloom, but make no mistake – the Bighead Knapweed is very invasive. It also features a large taproot that becomes more resilient with age. The leaves are lanceolate and 10 to 30 inches long with slightly pointed ends.
The leaf margins are typically smooth, dotted with short, fine hair, and covered with resin glands.
It has several common names, including Armenian basket flower, yellow hardhat, yellow Bachelor’s button, lemon fluff, and big yellow Centaurea.