REPORT

Invasive Plant Details

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Bighead Knapweed

Latin Name: Centaurea macrocephala

Priority Ranking: Regional EDRR

Identification

Flower: Large, bright yellow, thistle-like flower heads, typically blooming in mid to late summer.

Leaves: Dark green, oblong leaves with hairy undersides; basal leaves are larger and more robust.

Stems: Thick, sturdy, and unbranched, growing up to 1.5 meters tall.

Growing Environment: Prefers grasslands, pastures, and disturbed areas with well-drained soils.

Growth Habit: A robust perennial herb that can grow over 1 meter tall. It forms dense clumps or colonies with large, showy flower heads that dominate the landscape. The plant spreads through both seeds and rhizomes, allowing it to form substantial colonies over time. In situ, it appears as tall, towering stalks with prominent yellow flowers that rise above other vegetation.

Priority Ranking: Regional EDRR

Impacts on Environment

Impacts: Invasive in some regions, where it can aggressively spread and displace native plants by competing for light and nutrients.

Photo Credits: freenatureimages.eu - Ed Stikvoort