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Key identifying traits
Showy, yellow, primrose-like terminal flower clusters
Five petals and reddish brown calyx margins
Both the stems and leaves are softly hairy
Lance shaped, opposite or whorled leaves
Leaves are dotted with black or orange glands
Erect plant growing 4' tall or more
The fruit is a dry capsule
Biology and ecology
Perennial; spreads by seeds and rhizomes
Inhabits wetland and marshy sites
In our county, flowering period has been observed to be between July
and September
Reported to be out-competing purple loosestrife (no relation) in
western WA
Blooms are an indication of well established plants since young plants
dont appear to flower
Native of Eurasia, where it occurs in fens, wet woods, lake shores,
and river banks
Control
Prevention Learn to identify
plants; know your property; beware of ornamental starts and contaminated
recreational equipment
Biological None known and no research to date
Cultural In combination with other methods, competitive
vegetation & minimizing site disturbance helps
Mechanical Small infestations can be dug, bagged and disposed
of taking care not to disperse seeds; black plastic covers may be
effective with small patches; limited by rhizomes and moist sites
Chemical - Special care, permits and licenses
may be required if plants are growing in or very near water.
SCNWCB staff has has some success treating plants at bud-bloom stage
with tryclopyr mixed with a surfactant. Garden loosestrife
is not listed in the
PNW Weed Management handbook for specific chemical
recommendations |
flowers
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