Since 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.