Invasive Plants Identification Field Guide - Jun - Ministry of Forests
Invasive Plants Identification Field Guide - Jun - Ministry of Forests
Invasive Plants Identification Field Guide - Jun - Ministry of Forests
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Black knapweed<br />
Other common names:<br />
LeSSeR knaPweed<br />
Flower:<br />
Single, terminal flower heads with<br />
rose to purple or occasionally<br />
white flowers • Flower heads have<br />
triangular floral bracts with<br />
long black fringes<br />
leaves:<br />
Basal leaves hairy, stalked,<br />
toothed, up to 15 cm long • Stem<br />
leaves hairy, large, stalked, lobed •<br />
Upper leaves hairy, without stalks,<br />
entire margins<br />
stems:<br />
Erect, hairy, branched, 10 to 80<br />
cm tall<br />
roots:<br />
Vertical taproots • Spreading<br />
lateral roots<br />
Habitat:<br />
Moist soils at low to mid-elevations<br />
• Invades roadsides, riverbanks,<br />
disturbed areas, pastures and<br />
cropland.<br />
GrowtH Form and<br />
reproduction:<br />
Perennial forb • Reproduces by<br />
seed, infrequently by root shoots<br />
liFe cycle:<br />
centaurea nigra L.<br />
IaPP Code: BL<br />
impacts:<br />
Invades disturbed rangeland and<br />
reduces forage production. Can<br />
form dense stands.<br />
similar species:<br />
diffuse knapweed, smaller flower<br />
heads without triangle flower<br />
bracts. • Spotted knapweed,<br />
smaller flower heads without<br />
triangle flower bracts. • Brown<br />
knapweed, flower head bracts<br />
are hairy, wider at tips with thin,<br />
papery margins<br />
Britton and Brown 1913<br />
Province <strong>of</strong> BC
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