Tumble Knapweed
Centaurea diffusa
Last reviewed: June 2026
Light
full sun
Water
low
Size
12"–36" H × 12"–24" W
Bloom
Jun, Jul, Aug
Native to
WY
Pollinators
bees, beetles
Browse plants for this ecoregion
Tumble knapweed is a biennial forb that grows 1-3 feet tall with small purple flowers blooming through summer. This invasive species breaks off at the base when mature and tumbles in the wind to spread seeds. It thrives in dry conditions and full sun but is considered a noxious weed in most western states.
In an HOA neighborhood
Tumble Knapweed takes more care to keep looking intentional in a front yard. Maintenance level: low. Consider it for backyard or mid-zone beds rather than the street edge.
Works well in: backyard only.
- Considered invasive/noxious weed in many areas
- Can spread aggressively and tumble to disperse seeds
- May look weedy and unkempt to neighbors
Wildlife value
While it does attract bees and beetles during its summer bloom period, this invasive plant displaces native species that provide better long-term habitat value.
Native range data from the USDA PLANTS Database and regional native plant society lists. Pollinator and host plant associations compiled from GBIF, iNaturalist, and published ecological literature.
Does Tumble Knapweed fit your yard? Open it in Pollinator Patch to check it against your sun, soil, and HOA-conscious filters.