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.
Usually grows prostrate, with trailing stems forming a mat from 1-10
feet in diameter
Opposite, compound leaves are divided into 4-8 pairs of small, oval
leaflets covered with fine hair
Yellow, 5-petaled flowers are up to ½" wide and are formed at
the leaf axils
When mature and dry, the 5-part fruit breaks into hard, tack-like
structures with sharp spines
Biology and ecology
Native to southern Europe, this annual spreads only from seeds that
can remain dormant 4-5 yrs
Grows best on dry sandy soils, but tolerates most soil types.
Intolerant of freezing temperatures
Foliage is toxic to livestock, especially sheep, when consumed in
quantity
The hard, spiny burs damage wool, are objectionable in hay, can be
injurious to livestock and will puncture bicycle tires and feet
Other names: goathead, Texas sandbur, tackweed
Control
Prevention –
Learn to
identify plants; pay particular attention at roadside pullouts and along
driveways; monitor tires, shoes, animals for burs
Biological – Two weevils, Microlarinus lareynii and M.
lypriformis, have been introduced into the U.S. and have given
reasonably good results
Cultural – Healthy, competitive vegetation can protect against
this invader
Mechanical – Tillage is effective prior to seed production.
Hand-pulling is preferred for small infestations. Mowing is ineffective
due to the prostrate growth habit
Chemical – Many herbicides are reported to be effective, either
pre-or post emergent;
refer to the
PNW Weed Management Handbook for specific chemical recommendations
Where found –
The
only known plant in the county was found in 2004 at a pull-out off of
Hwy 395, just east of the Columbia River bridge outside of Kettle Falls.
Report any sightings please!
