Purple
loosestrife is a native forb of Europe. It is a taprooted perennial;
short rhizomes also exist. This plant is considered a noxious weed
and is included on the Colorado and the Adams County Noxious Weed
Lists. Purple loosestrife has escaped from ornamental plantings
to aquatic sites such as riverbanks, ditches, shorelines, and wet
meadows. Infestations rapidly replace native vegetation, can impede
water flow in canals and ditches, and have little wildlife habitat
value.
This
noxious weed spreads primarily by seeds carried in water, in fur
of feather of animals, and from human activities. One mature plant
can produce up to 3 million seeds per year! Seeds survive in the
soil for 5 to 20 years. Pieces of roots or stems also can produce
new plants. Purple loosestrife produces multiple stems, 2 to 8 feet
tall and 4-sided. They can either be smooth or hairy. Leaves are
opposite or whorled on stems, 2 to 5 inches long, tongue-shaped
with pointed tips and attached directly to the stem (no petiole).
Flowers are reddish-purple in color and have 5 to 7 petals.
