DRWA logo
Deerfield River Watershed Association
Invasive Plants
Knotweed Control
Native or Exotic?
Plant List
What can you do?
More Info
Back to Ecology

An increasing problem in the Deerfield River watershed

MET Awards Grant to DRWA

to MET The Deerfield River Watershed Association is pleased to announce an award of $15,000.00 from the Massachusetts Environmental Trust to manage the invasive plant, Japanese knotweed, in rivers and streams throughout the watershed. Japanese Knotweed, a native of Eastern Asia, is a fast-growing perennial that forms dense thickets along stream banks and roads, and in yards and disturbed areas. With this funding, the Association will begin removing knotweed from selected rivers and streams and design an outreach program to provide the watershed community with practical information on the identification and management of knotweed. The DRWA will be working with a diverse group of community members to tackle this wide-spread problem, including Trout Unlimited, Massachusetts Riverways Program, Conte National Fish and Wildlife Refuge, and local municipalities and landowners, among others.

The Association is seeking volunteers to help biologists survey and remove knotweed in several rivers and streams in the watershed in the spring of 2006. Please call or email Pat Serrentino at (413) 772-0520; pserr@crocker.com if interested in volunteering for the project or if you have any questions.

This project is made possible by the generosity of motorists who choose to purchase one of the Massachusetts Environmental Trust's specialty license plates. The Trust will provide close to $1 million in grants to over 40 organizations this year. These grants provide funds for programs that preserve the state's rivers and streams, protect rare species, and educate communities about environmental issues. Please go to www.MassEnvironmentalTrust.org to learn more about the Trust, the programs it supports, and the specialty license plate offerings.

to top

Native vs Exotic

If you drive down the road or highway, take a walk in your neighborhood, or go fishing in your favorite river or stream, there’s a good chance you have seen several invasive plant species. In the Deerfield River watershed you would most likely encounter Asiatic or Oriental Bittersweet, Bishop’s Weed, Multiflora Rose, Japanese Knotweed, and Garlic Mustard, among others.

Before going any further, however, there are several terms we should define. A native plant is one that has grown in a particular geographic area for long periods of time. A non-native plant (or alien, exotic, introduced plant) is one that occurs outside its natural range, and was brought to a new site or several sites through human activities. For example, a non-native plant in Massachusetts may have originally come from Asia or Africa, but also could have come from the West Coast of the United States. Non-native plants have many uses in our lives. We use them as food sources, derive medicines from some, and enjoy them in our gardens. However, when a non-native plant exhibits certain characteristics, it’s considered invasive.

to top


A plant is invasive in an area if it grows rapidly and is difficult to remove or control once established. High seed production and/or germination rate, or the ability to spread rapidly by their rhizomes or root systems are other features of invasive plants. Obviously there are many non-native plants that do not behave in ways that are harmful to the natural environment. We’re not worried about these plants.

What is it that allows some non-native plants to become invasive?

A non-native species may become invasive in its new environment because it does not have any natural predators and diseases to keep its growth in check or to prevent its successful reproduction. In their new environment they also may not have any natural plant competitors so they are able to grow unchecked.

How do these plants actually harm the natural environment?

Characteristics of invasive plants that allow them to alter natural environments are the following:

• Plants physically take over the space around them which prevents native plants from growing in the same area.

• Plants change their immediate environment by altering the amount of sunlight, water, and nutrients that are available to other plants and organisms.

• On a larger scale, invasive plants can actually decrease the variety and number of native plants that are available to wildlife and other organisms, for food, shelter, and breeding or nesting sites.

When invasive species take over large areas of habitat, ecological processes are changed. This occurs because the plants and animals in an area have evolved together for thousands of years, which results in a complex web of species interactions. For example, many butterfly and moth species require specific food plants for their caterpillars or larvae. Some birds prefer to nest in or forage on particular plant species.

to top

List of Invasives in the Watershed

Here is a list of some species that pose the greatest threat to natural communities in Massachusetts. These species were selected from a list published by the Massachusetts Invasive Plant Working Group (2003). Many of these plants are found in more than one habitat type.

Wetlands (marshes, shrub swamps, wet meadows)

Purple Loosestrife (Lythrum salicaria)
Phragmites or Common Reed (Phragmites australis)
Shining Buckthorn (Rhamnus frangula)
Yellow Iris (Iris pseudacorus)

Floodplains and Stream Banks

Morrow’s Honeysuckle (Lonicera morrowii)
Japanese Knotweed or Bamboo (Polygonum cuspidatum)
Goutweed or Bishop’s Weed (Aegopodium podagraria)
Garlic Mustard (Alliaria petiolata)

Open Habitats (fields, right-of-ways, parks, cemeteries)

Black Locust (Robinia pseudoacacia)
Oriental Bittersweet (Celastrus orbiculatus)
Japanese Barberry (Berberis thunbergii)
Multiflora Rose (Rosa multiflora)


Japanese Barberry (Berberis thunbergii)
Multiflora Rose (Rosa multiflora)
Garlic Mustard (Alliaria petiolata)
Common Buckthorn (Rhamnus cathartica)

Ponds, Lakes, Rivers

Water-chestnut (Trapa natans)
Variable Water-milfoil (Myriophyllum heterophyllum)
Eurasian milfoil (Myriophyllum spicatum)
Fanwort (Cabomba caroliniana)
Curly-leaved pondweed (Potamogeton crispus)

to top

What Can You Do?

There are several things you can do to prevent the spread of invasive plants. First, learn to identify invasive plants, and native ones, too. There are many resources in your local library, bookstore, and on the internet. For example, guides to plant identification are a good place to start. The Massachusetts Invasive Plant Working Group has recently published a list of plants that are considered invasive in Massachusetts.

Don’t plant invasive species in your garden – use native species and non-natives that tend to stay put. Encourage your neighbors to do the same. If you discover an invasive species in your yard or garden, remove it immediately. Since moving to my current home, I have found several invasive plants in my yard – including Norway Maple, Asiatic Bittersweet, and Japanese Barberry.

If you’re visiting a public or private nature reserve or park, report any sightings of new or small patches of known invasive species to the land manager. It’s much less expensive and time-consuming to stay ahead of infestations if they’re controlled at the first sign of invasion.

You can also get involved in local garden clubs and conservation organizations. Spread the word about the impacts of invasive plants to native biodiversity and help with projects that identify and remove invasive plants in your area.

The DRWA has conducted an inventory of several tributaries of the Deerfield River for Japanese Knotweed, a fast-growing perennial that has already taken over acres of stream bank on the Deerfield River, and has spread into many tributaries. This native of Eastern Asia can grow as tall as 18 feet and quickly forms large thickets that out-compete native plant communities. It tolerates a wide variety of environmental conditions, is fast-growing, and spreads by both rhizomes or roots and seeds. It is one of the few invasives that have become a problem in places as far away as Alaska. We hope to begin removing the plant at selected sites in 2004. If you’re interested in participating in future plant surveys or removal efforts, please contact Pat Serrentino at (413) 772-0520.

To learn bout eradication of Japanese knotweed, read the article in the Fall 2004 Current.

Results of the 2003 Japanese Knotwed Survey:
Avery Brook: Most of the entire length of this stream was surveyed. Patches were confined to two locations: (1) just south of where Burrington Road enters Avery Road, and (2) at the confluence of Avery Brook and the Deerfield River.

Bear River: Approximately 3.4 km of the Bear River was inventoried. Patches of knotweed were found in both areas that were surveyed - from the portion that flows between Pfersick Road and Shelburne Falls Road, and where the Bear flows into the Deerfield River. However, most of the Bear was not surveyed.

Chickley River: About one-third of the Chickley River was surveyed. Unfortunately, knotweed was abundant and well-distributed along the portion that flows between West Hawley and southwest of Forge Hill. No knotweed was found in the section upstream of West Hawley. The headwater area (upstream of where Brown Brook enters) was not surveyed.

Clesson Brook: Approximately 70% of the Clesson’s 19.6 km length was surveyed by foot, car, and bicycle. Very little knotweed was found between Cox Ponds and where Cooley Brook enters the Clesson. Knotweed was growing in an almost continuous patch between Buckland Four Corners and the Clesson’s confluence with the Deerfield River.

Green River: The Green River, at almost 32.5 km, was the longest river surveyed. About 50% of the River’s length was inventoried. The distribution of knotweed varied with location. In general, upstream of West Leyden knotweed was found in small patches and single plants. Downstream of where Workman Brook entered the Green, knotweed patches increased in both number and density. Similar to what was observed on the banks of Clesson Brook, knotweed patches were almost continuous between the Rte. 2A bridge and where the Green enters the Deerfield River.

Sanders Brook: Most of this brook is located in H.O. Cook State Forest in Heath. About 50% of this beautiful, high velocity stream was surveyed and one patch was found – where it enters the West Branch of the North River at Adamsville Road. Most of the lower end of the brook was not surveyed because it is on private property.

South River: Approximately 40% of the South River was surveyed. Because this river is close to 30 km long, it was difficult to survey the entire reach. Very little knotweed was found from between where the river exits Ashfield Lake to the Bullitt Road crossing. However, just upstream of where the South empties into the Deerfield River (in the South River State Forest) huge patches of knotweed were found.

Tannery Brook: This brook flows from Tannery Falls in Savoy Mountain State Forest, to Gulf Brook. For 1.3 km it flows through heavily forested, steep terrain. Happily, no knotweed was found along the banks of this brook.

See 2003 Report:

  • Japanese Knotweed Inventory of Selected Tributaries of the Deerfield River(PDF file)
  • Maps with survey results (PDF file warning: 9MB!)

to top

Additional Information

At many of these sites you can look up specific plants and see a photograph or picture, learn about its specific characteristics, and at some sites, methods for controlling it.

New England Wildflower Society: General information; links to the Massachusetts Plant List

Invasive Plant Atlas of New England (IPANE): General information, plant descriptions, and volunteer surveys

Invasivespecies.gov: Government website with general information on invasive plants and animals

Weeds Gone Wild: This Plant Conservation Alliance’s site has all kinds of information and is easy to use

Garlic Mustard Control Presentation Available Online
With Garlic Mustard season upon us, this is a good time to learn more about this plant.  Check out this EXCELLENT taped webcast from The Stewardship Network based in Michigan.  It covers the biology of the plant and control measures, including good tips for better control.  It takes about 45 minutes (with an extra 15 of discussion and questions) and is well worth the time.  It also would be a good tool if you are using hand pulling with volunteers to educate them on the project. Webcast is online at: http://breeze.cvm.msu.edu/p37329821/

The Connecticut Agricultural Experiment Station's Invasive Aquatic Plant Program now has a website
where you can find:
general information about the program; survey results, including colorful maps; descriptions of the invasive aquatics; volunteer information; form to request a survey of a lake; legislation concerning aquatic invasive plants; management information; publications; links to other helpful sites;  contact information.

Do you have suggestions or would like to contribute content to this page? Please contact drwa@deerfieldriver.org

This web site made possible in part by the Valley Charitable Trust Fund administered by Fleet National Bank,
and by the Community Foundation for Western Massachusetts

Revised 2/22/11 by MF Walk . DRWA HOME