Stevens County Noxious Weed Control
Board This web site will help
you identify & control noxious weeds. Conventional & biological control
(BioControl) information and photographs are here. Maps & related
information are included.
Showy pairs of yellow-green, heart shaped
bracts (often mistaken for flowers)
Entire plant contains a milky juice (sap)
Roots are extensive with pink buds for new
shoots or roots
Leaves are alternate, narrow, 1-4"
long
Single stalks or multiple stems, up to 3' tall
True flowers are yellow-green but
inconspicuous
Seeds are contained in a 3-celled capsule
Biology and ecology
Perennial; reproduces by vigorous root stalks and seed; seed capsules
explode when dry, projecting seeds up to 20'
Sap can cause extreme irritation to man or beast
Native to central and southern Europe, and eastward through most of
Asia
Invades a wide variety of sites- dry hillsides, wet meadows, riparian
areas, roadsides
Once plants are well established (3 years) large nutrient reserves in
the extensive root system make control difficult & expensive and
eradication nearly impossible
Forms dense stands which only goats/sheep graze
Control
Prevention
- Learn to
identify the plant; know your property; beware of fill dirt, hay and seed
from outside your area
Biological – Several used in combination with sheep and with
herbicides to combat extensive infestations in the mountain west; trial
colony only in Stevens Co
Cultural – Competitive vegetation helps but does not stop
infestations
Mechanical – Persistent, almost zealous digging or cultivation is
required to be at all successful
Chemical – A few are effective if applied using the correct rates,
timing, mixtures, and adjuvants; generally requires a licensed operator.
Refer to the
PNW Weed Management Handbook for specific chemical recommendations
mature plant
white, latex sap
yellow-green bracts
surrounding true flowers
immature plants
spurge roots
Where found -
Small
infestations found scattered around Stevens County; active ID and cost
share control programs have limited the acres involved to less than 100.
