Spotted Knapweed
Scientific Name: Centaurea stoebe
Category: plant
Brief Description
An invasive herbaceous plant known for its pink-to-purple thistle-like flowers and deeply divided, grayish-green leaves.
Characteristics
Stiff stems growing up to 2-3 feet tall, deeply lobed or divided grayish-green leaves, and solitary pink-purple flower heads with dark-tipped bracts that give the bud a spotted appearance.
Habitat
Disturbed soils, roadsides, pastures, grasslands, and dry open areas.
When to Find It
Flowers typically from June through September.
Conservation Status
N/A
Ecological Role
Highly invasive weed that outcompetes native vegetation, reduces biodiversity, and degrades wildlife habitat and forage quality.
Easily Confused With
Diffuse knapweed (Centaurea diffusa) which has white or occasionally purplish flowers and widely spreading spines on the bracts.
Observation Tips
Observe in sunny open fields and along roadsides during mid-summer. Wear gloves if handling as it can cause skin irritation in some individuals.
Interesting Facts
Spotted knapweed releases allelopathic chemicals from its roots that inhibit the growth of surrounding plants, helping it dominate ecosystems.