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Key identifying traits
Small (< 1inch), golden, daisy-like flowers are arranged in
clusters at ends of stems
Single or multi-branched; 1-6 feet tall
Leaves 2 to 8 inches long, alternate, deeply lobed
Irregular, deeply cut leaf segments give "ragged" appearance
Observed at a distance (mainly during flowering), plant structure
resembles St. Johnswort
Biology and ecology
Biennial to short-lived, tap-rooted perennial
Reproduces by seed; flowers July to September
High alkaloid content makes all plant parts toxic to cattle, horses
and, to some extent, sheep
Invades log landings, roads and other openings in forested areas;
widespread in western WA and OR
Control
Prevention – Learn to identify
plants; know your property; beware of equipment/vehicles recently used in western
WA or OR and not thoroughly cleaned
Biological – Three established agents are working well in western
WA, OR and CA; not practical for the small amounts of plants found in
eastern WA
Cultural – Competitive vegetation helps reduce open spaces for
invasion
Mechanical – Digging or pulling when soil conditions are moist is
effective; needs to be before bloom or, if after, bag or burn plants in a
pile as appropriate; seed bank will be present for years
Chemical - Several effective at label rates; best timing is spring
during rosette stage; new infestations are usually identified when in
flower, requiring a combination of mechanical and chemical control over
more than one year;
refer to the
PNW Weed Management Handbook for specific chemical recommendations |
flowers
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