REPORT

Invasive Plant Details

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Black Knapweed

Latin Name: Centaurea nigra

Priority Ranking: Regional EDRR

Identification

Flower: Purple, thistle-like flower heads that bloom from mid to late summer.

Leaves: Basal leaves are lance-shaped and deeply lobed, while upper leaves are narrower and slightly hairy.

Stems: Erect, branched, and hairy, reaching up to 1 meter in height.

Growing Environment: Found in meadows, pastures, grasslands, and disturbed areas.

Growth Habit: A perennial herb that forms dense clumps or patches. It grows up to 1 meter tall and spreads primarily through seeds. In situ, Black Knapweed can form extensive stands, particularly in open meadows and pastures, often becoming the dominant plant species due to its competitive nature.

Priority Ranking: Regional EDRR

Impacts on Environment

Impacts: Invasive in many regions, particularly in grasslands, where it can outcompete native vegetation.