Purple Loosestrife
The purple loosestrife is an invasive, noxious weed that causes damage to Colorado's ecosystem.
About This Species
Purple loosestrife is not native to Colorado. It is classified as a "List A" species in the Colorado Noxious Weed Act, designating it for statewide eradication.
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Physical Characteristics
Purple loosestrife is a perennial forb that grows 6-8 feet tall. The 1-inch-long flowers are pinkish-purple with 5-7 petals in long racemes. he flowers are tightly grouped in long, vertical heads, and bloom from the bottom up. The distinctive stem is 4-sided, and the leaves are lance-shaped with smooth edges. Its leaves are two to five inches long, and whorled on the stems. Purple loosestrife has a taproot, making it difficult to remove mechanically (hand-removal). This species may be mistaken for native fireweed (Chamerion augustifolium).
Habitat
Purple loosestrife is an escaped ornamental that prefers river banks, stream banks, shallow ponds, ditches, shores of lakes and wetlands throughout the state.
Reproduction
The flowers usually emerge from late June through September, 8-10 weeks after germination.