Greater Knapweed
Greater Knapweed
Centaurea scabiosa L.
Asteraceae (Sunflower Family)
▲ ▼ first year rosettes
▲ hairy leaves, above and below
▲ plant starting to produce flower heads
▲ ▼ inflorescence/flower buds, showing the unique, dark, comb-toothed bracts
Centaurea scabiosa L., Greater Knapweed: (Bayer Code: not known; US Code CESC2)
- Simple perennial plant with stout rootstock native to Europe and found escaped from cultivation in northern Midwest in some areas
- Basal leaves are deeply, pinnately-lobed, with oval, pointed-tip lobes; flowering stem leaves usually have narrower lobes
- Stems are generally unbranched, and head inflorescences are at the tip of these stems; pre-flowering heads are nearly spherical
- Heads have pinkish-purple ray flowers, and bracts edged with dark brown or purple tiny teeth that spread away from the base of the head
- Not a problem yet in Missouri
- Similar Black Knapweed (Centaurea nigra) has mostly smooth-margined or slightly toothed or lobed leaves and the spine-like dark teeth are confined to the tip section of the bracts below the inflorescence, rather than along most of the margin of the inflorescence head bracts, as in greater knapweed
- Similar Brown Knapweed (Centaurea jacea) has brown, papery edges to the bracts underneath the head inflorescence
(Posted January 23, 2019)