Provincial Noxious. Biennial or short-lived perennial.
A bushy plant growing 0.3 to 1.2 metres tall, with many deeply-cut leaves,
giving it a ragged appearance. The flowers are bright yellow, daisy-like,
and grouped in flat-topped clusters.
Tansy ragwort reduces forage production of pastures by up to 50%.
It contains alkaloids that can poison livestock, although the plant is
often avoided. Trace amounts of the alkaloids found in milk and honey
produced from infested pastures raise concerns for human consumption.
In British Columbia, tansy ragwort grows on disturbed
sites in pastures, hay fields, roadsides, and clear cuts. It is a
major concern in the Lower Mainland and southern Vancouver Island and
is also present in the Okanagan.
A single plant can produce 150,000 seeds which can remain viable
for over 20 years. Seeds are dispersed by wind, water, and animals.