IDENTIFICATION
Biennial.
Nodding thistle has a large, deep reddish-purple flower with a bract
like a collar of spine-tipped points. On maturity the flowers droop or
"nod." The dark-green leaves, which often have white edges,
are deeply lobed or cut and have spines.
Mature plants can grow to 2.5 m tall.
DAMAGE
As livestock will not eat nodding thistle it reduces pasture production.
It invades pasture, rangeland, forestland, cropland, and disturbed areas
where it spreads rapidly and forms extensive stands. Nodding thistle
may produce allelopathic chemicals that inhibit desirable plants.
HABITAT
Nodding thistle is found along dry roadsides and disturbed habitats
at mid-elevations. It does not appear to have any specific climatic requirements,
other than a cool period before flowering. It occurs in isolated pockets
in the Chilcotin, Thompson, Nicola, Kootenay, Okanagan, Similkameen, Boundary,
and Bulkley Valley areas of BC.
SPREAD
A single plant produces 10,000 seeds but has been known to produce 100,000.
Seeds are dispersed by wind, water, wildlife, and livestock.
