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Purple Loosestrife

Lythrum salicaria

Description:  a purple flowering perennial that can grow up to 10 feet tall.  In Oklahoma, it flowers in the late summer on multistemmed plants. Native to Europe and Asia, it was first introduced into North America in the early 1800s for ornamental and medicinal purposes.


Ecological Threat: a serious invader of many types of wetlands, including wet meadows, prairie potholes, river and stream banks, lakeshores, tidal and nontidal marshes, and ditches. It can also hybridize with native loosestrife species, potentially depleting the native species gene pool.


Biology & Spread: It can quickly form dense stands that completely dominate the area excluding native vegetation. This plant can spread very rapidly due to its prolific seed production; each plant can produce up to 2.5 million seeds per year.


In Oklahoma: the first record of Purple Loosestrife in Oklahoma was from 1993.  Unlike the rapid infestation of wetlands and lake margins in the eastern U.S., it has not become a significant invasive plant in Oklahoma since its introduction.

Management: Aquatic Weed Management, OSU Extension Factsheet


Additional Information: Problem Horticultural Plants, OSU Extension Factsheet

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