Combatting Purple Loosestrife

Purple loosestrife (Lythrum salicaria) is an invasive species native to Europe and Asia which can be described as a perennial with a woody and square stem with purple flowers. L. salicaria can grow upwards of 6 feet and in Indiana, starts to bloom in July and into September. This wetland plant was introduced to the United States by cargo ships passing through the Great Lakes and by transportation of seeds from its native region. The first recorded sighting in the United States was in the early 1800’s. Since its introduction in the United States, and before it was considered an invasive species, it was often planted and sold as a decorative ornamental. Purple loosestrife has since been found in most of both the United States and Canada.

L. salicaria can overtake the landscape and outcompete natives, resulting in a potentially less biodiverse ecosystem and unsuitable shelter and food for most species relying on the native plants within. L. salicaria spread quickly and create dense canopies that are hard to penetrate, resulting in insufficient shelter for native wildlife. The chemical composition of the plant can also alter the chemistry of the surrounding area, creating non-favorable conditions for local wildlife.

Over 2.5 million seeds can be produced (and potentially spread) by one plant annually. Ways to stop this invasive include using herbicides with components such as glyphosate or triclopyr, or by pulling smaller clumps, but bigger clumps tend to have an extensive root system that cannot be removed easily by hand. Here at Wellfield Botanic Gardens, we cut L. salicaria and apply herbicide directly to the cut stem.

Invasive purple loosestrife is found all over Michiana; we can all do our best in the eradication of invasive species to help the natives in our area rebound and flourish. So, lookout for purple loosestrife in your neighborhood and get to gardening!

Ariana Guerrero

Horticulturist

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