Pushing Back Against Invasive Plants

By Chris Rimmer

Dreaded exotic insect pests like emerald ash borer and Asian long-horned beetle are knocking on Vermont’s doorstep. These destructive invaders could cause massive changes to our state’s landscape in years to come. However, Norwich’s woods, fields, roadsides and waterways are already home to an astonishing array of well-established, non-native plants. Many of these “invasives” have become so familiar that we don’t always recognize them, let alone realize their profound impacts on our native ecosystems. But, make no mistake: these opportunistic intruders have begun to dominate our landscape, and will continue to if allowed to spread unchecked.

Whether growing on land or in water, invasive plants take a heavy toll: by disrupting ecosystem function and productivity, crowding out native wildlife, altering soil chemistry, hastening erosion, even posing direct risks to human health. And, the economic costs of combatting invasives are anything but trivial. In Norwich, invasives have dramatically increased during recent decades, both in diversity and abundance. Our summer roadways are choked with a procession of noxious, weedy plants like wild chervil and poison parsnip, while our forests and fields are being overtaken by glossy buckthorn, Japanese barberry and autumn olive. Even our riverbanks and shallow waters are falling prey to the likes of Japanese knotweed, purple loosestrife and common reed. What’s a concerned citizen to do?

The Norwich Conservation Commission (NCC) is tackling the issue of invasives head-on in 2016. Our goals are to inform citizens about the threats these non-natives pose, develop coordinated strategies to reduce populations of selected species within Norwich, and galvanize townspeople to participate in taking action. Our approach will be to:

  • Focus each quarterly Norwich Times column on one or two invasive troublemakers
  • Hold public forums to promote more in-depth learning
  • Lead periodic field trips to identify, map and control selected invasives
  • Recommend management practices that individual citizens can take to prevent invasives from becoming established, limit their spread and/or reduce their infestations

This month we’ll highlight one common invader: burning bush, or winged euonymus (Euonymus alatus). This exotic from northeastern Asia was introduced to North America in the 1860s and is widely planted for its desirable ornamental features, attractiveness to wildlife (the berries are edible), and adaptability to diverse horticultural environments. Famous for its flame red autumn foliage, burning bush has long been a popular landscaping choice. Yet, it exhibits the classic traits of successful invasives: high seed production, dispersal of fruits by birds, both sexual and vegetative reproduction, avoidance by predators, and broad ecological tolerance (it grows in both shade and sun). Escapees from cultivated ornamentals are widely dispersed throughout Norwich, especially along wooded roadsides, where they crowd out native understory species. The plant is readily identifiable at any time of year by its corky-winged stems. Control measures range from “cultural” (avoid planting the species and educate others likewise), to mechanical (pull, dig and cut), to chemical (herbicides, always the least desirable option). There are no known biological control agents.

Winged euonymus has already joined the list of invasive plants whose importation, trade, sale and cultivation are banned in Vermont. If you have burning bush established around your home, strongly consider removing it and planting native replacements, such as blueberries, spicebush, elderberry, or Viburnum. Encourage others to follow suit – please do not plant this attractive non-native!

Vermont has several active efforts to educate its citizens about invasives and to control their spread. Check out the Vermont Invasives website and please join the NCC in our efforts to keep Norwich’s diverse plant communities healthy and (mostly) free of non-natives!

Originally published in Winter/Spring 2016 Norwich Times