Key identifying traits
- Waxy yellow flowers with
5-9 petals
- Plants usually grow
6-12” tall but flower heads can extend to 24” on stems with few
leaves
- Leaves are hairy with
long petioles (leaf stems), are dark green & 3-parted with
toothed margins
- Globe-shaped seed heads
contain from 12-50 fruits each
Biology
and ecology
- A creeping perennial
spreading by seeds as well as hairy stolons that form roots &
daughter plants at lower nodes
- Prefers moist or poorly
drained soils, but can colonize gravelly banks as well;
withstands flooding
- It is toxic to livestock
in pastures but not when dried in hay but is not generally
utilized
- Introduced from Europe
as an ornamental, now widely established in the U.S.
- Does not compete well
with a good grass stand but can be aggressive in moist,
overgrazed pastures, roadsides and waste areas
Control
Prevention –
Learn to identify plants; start monitoring early in the season
Biological –
No known biological control in our area
Cultural –
Plant competitive grass or other cover crop
Mechanical –
Cultivation can be effective if repeated to prevent stem fragments
from starting new plants; mowing is not a good control method
Chemical – MCPA is often
recommended for control: refer to the
PNW Weed Management handbook for specific chemical
recommendations.
|
© 2004, Ben Legler:, WTU Herbarium, U
of Washington |
