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Key identifying traits
Blue flowers with pink stamens arranged on the upper side of short,
scorpion-tail stems; as the stem straightens flowers open a few at a
time, stalk to tip
Stems and leaves are covered with stiff hairs which are swollen at the
base; wear gloves when handling to avoid having the stiff hairs end up
in your flesh!
Swellings have a reddish or blackish tint giving the stem a flecked
appearance
Single stalks or multiple branches 1-3'tall
Biology and Ecology
Biennial to short-lived, tap rooted perennial
Reproduces by seed and can re-grow from crown
Flowers June through early fall
Seeds are produced in a four-part nutlet and are very hard and
long-lived
Thrives in sunny sites-does not tolerate shade
Native to Europe
Invades lawns, ornamental areas, roadsides and range land
Control
Prevention-
learn to identify plant; know your property; beware of fill dirt, hay and
seed from outside your area
Biological- no known biological controls approved for
Blueweed at this time
Cultural- competitive vegetation helps; keep lawns healthy (water/feed) to
increase the vigor of turf and reduce open spaces for invasion
Mechanical- mowing can stop seed production in short term, but
plants can re-grow and bloom shorter than the cutting blade; digging or
pulling when soil conditions are moist is effective-control prior to bloom
or, if after, bag or burn plants in a pile as appropriate; seed bank will be present for years
Chemical-
Difficult due to the hairs-best with adjuvant
added to help penetrate through hairs; best
timing is in early spring when plants are in the rosette stage;
the
PNW Weed Management Handbook does not list this weed, but
recommendations for other biennial/perennial borages might work. SCNWCB
staff has had luck with glyphosate, 2,4-D alone if plants are very small
or in combination with dicamba and/or metsulfuron if plants are older |
Digging mature blueweed
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