knapweed

American  

[nap-weed] / ˈnæpˌwid /

noun

1. any composite plant of the genus Centaurea, especially the weedy C. nigra, having rose-purple flowers set on a dark-colored, knoblike bract.

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knapweed British  

/ ˈnæpˌwiːd /

noun

1. any of several plants of the genus Centaurea, having purplish thistle-like flowers: family Asteraceae (composites) See also centaury hardheads

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Etymology

Origin of knapweed

First recorded in 1400–50, knapweed is from the late Middle English word knopwed. See knop, weed ¹

Example Sentences

Certain species such as cow parsley, yarrow and knapweed are in fact spreading, and he welcomes an influx of non-native plants and "garden escapes", such as snowdrop and buddleia.

From BBC

As far as I know, farmers are fine with knapweed.

From Seattle Times

In time, up came indigenous plants like knapweed and yellow rattle and more exotic blooms like Camassia, byzantine gladiolus.

From New York Times

Working Dogs for Conservation has trained dogs to find spotted knapweed in Montana, Chinese bush clover in Iowa, yellow star thistle in Colorado, rosy wolf snails in Hawaii and brown tree snakes in Guam.

From Washington Times

These include tufted vetch, bugle, tormentil, red clover, lady's bedstraw, white campion and greater knapweed.

From BBC