Monday, September 8, 2014

Caitlin Stewart: Making a Dent in Purple Loosestrife

Purple LoosestrifeSince 2003, I have been battling purple loosestrife, an invasive plant that may be gorgeous but overruns wetlands, and outcompetes native plants that wildlife and waterfowl depend on for food, shelter, and nesting grounds. After 11 years of manual management, populations along the Route 8 and Route 30 corridors in Hamilton County have decreased. This is good news for native plants that fill in areas where invasive purple loosestrife used to grow.

This August I focused on rights-of-way along Routes 8 and 30 in the Town of Lake Pleasant and the Village of Speculator. I snipped each flower with garden clippers before plants went to seed for reproduction. All plant material was bagged and allowed to liquefy in the sun before being delivered to a transfer station.

It is exciting to fight invasive plants for over a decade and see promising results like this. Manual management is tedious, but persistent efforts have helped stop the spread of purple loosestrife and remove these invaders from the environment.

Purple loosestrife was introduced to North America in the 1800s. Colonists brought the plant over from Europe as an ornamental and for medicinal uses in tonics. Ship ballast water held seeds and was emptied into ports. It is often planted in gardens. Without the ecological checks and balances found on its home turf, purple loosestrife can quickly reproduce and spread.

This perennial has showy, magenta flowers that bloom from July through September. Plants can tower 10 feet high and produce 2.5 million seeds each year. Broken roots have the ability to re-sprout. Seeds and fragments are spread by wildlife, wind and water movements, mowing, and vehicles.

I received a biocontrol permit from the Department of Environmental Conservation that allowed for the release of Galerucella beetles along the Sacandaga River and the Speculator Pavilion. These beetles have a voracious appetite and munch on leaves, preventing purple loosestrife from making food (sugars) during photosynthesis. As sugar production decreases, new shoots and roots are not produced, and stunted plant growth and eventual death result. Galerucella beetles depend solely on purple loosestrife to complete their life cycle, and as plants die back, beetle populations crash.

I surveyed the beetle release sites this past June and spotted adult beetles along with purple loosestrife leaves that showed the characteristic shot-hole feeding damage. Thanks to the beetles, plant populations were not nearly as dense as in previous years.

During manual management this August, I was thrilled to come across beetles and leaf feeding damage along Route 8 in Speculator. Hungry beetles flew from their home a few miles down the road to these new locations in search of purple loosestrife. I left these insects alone to do their job.

The one – two punch of manual management and biocontrol has put a dent in purple loosestrife. Clipping flower spikes before they go to seed slows reproduction and decreases populations over time while Galerucella beetles are a fantastic biocontrol method. It is incredibly satisfying for me to see those purple blotches along Hamilton County roads diminish.

Photo: A large stand of invasive purple loosestrife that grew along the shoreline of Lake Pleasant, now removed.

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Caitlin Stewart manages the Hamilton County Soil and Water Conservation District. The District's mission is to manage and promote the wise use of Natural Resources in Hamilton County. Caitlin will be sharing the District's conservation-focused services, programs, and events. She’s been a full time resident of Hamilton County since 2008 and is an avid hiker, skier, paddler, and biker. She is obsessed with adventuring with her dog Artemis.

10 Responses

  1. Terry says:

    Keep up the good work! Hopefully many will read this post and ‘join the fight’ against this invader (pretty as it may be)!! 🙂

  2. Laurie says:

    Well done, and thanks for inspiring others to now do the same.

  3. Caitlin Stewart says:

    It is wonderful and exciting to see Adirondack communities, Lake Associations and other organizations, and municipalities so passionate about invasive species. Within the last few years invasive species have come to the forefront of conservation initiatives. Publications like the Adiorndack Almanack and beyond highlight invasive species. They even made the cover of TIME magazine. New York State has seen invasive species legislation pass to help protect our environment, economy, and public health and safety at the local and state level. Efforts that help stop the spread of invasive species are making a tremendous difference. Bravo to all involved.

  4. Dick Carlson says:

    Hi Caitlin – Good work. I have been stopping along Rt. 28 and other roads in Warren County if I see any PL. The State DOT (Warrensburg) in their infinite wisdom decided to spray all the guardrails with herbicide but not mow any of the road sides. They skipped right by PL in many areas. I question the wisdom of applying the herbicide to the guard rails it they’re not going to mow – just looks ugly brown. And what? Do they think it somehow protects the guardrails? And again the PL got off scott free!

    • Caitlin Stewart says:

      Thank you for your comment, Dick, and for your work to manage invasive plants like purple loosestrife.

  5. Jim Fox says:

    I never knew that PL could be eradicated. Thanks for this article, Caitlin, and moreso, proof that what you’ve done has been effective!

  6. Charlie Herr says:

    Route 28 was repaved by the state or county a few years ago and immediately the next year, thousands of these purple blossoms turned up. I didn’t know if these were planted by the highway folks when they sprayed seed and fertilizer on the sides of the new surfaced highway. Is this possible that it was part of that groundcover program that they included this invasive plant?

    • Caitlin Stewart says:

      Thank you for your comment, Charlie. I do not know the answer to your inquiry. You may want to follow up with the local or county Highway Superintendent.

  7. Mickey B says:

    Nice to know that just pulling the blooms off before seeding is helpful and slows growth.
    Will do, carefully.

  8. Hello, Caitlin! I am most interested in the status of the Galerucella beetle studies you conducted. You and I corresponded about them last summer via my OurLakes blog.
    Are further trials being conducted? Any way to request a release in a small area of Saratoga County?
    Best wishes for continued success against Purple Loosestrife!
    Suzanne McGraw

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