A community coalition to rid Newtown, Connecticut of the invasive weed that blocks visibility along our roadsides, takes over streambanks, and pushes out native plants.
Japanese knotweed thrives in disturbed areas, like roadsides, as well as stream and riverbanks. You may have already seen it, not realizing what it was. Due to its extensive underground root system, Japanese knotweed quickly dominates an area, out-competing other plants while withstanding shade, drought and high temperatures.
Knotweed suppresses the growth of neighboring plants, alters soil chemistry, contributes to erosion and floods, and jeopardizes streambank stability. It reduces the number of aquatic macroinvertebrates, which are an integral part of the aquatic food chain.
Property damage caused by Japanese knotweed includes infiltration of structures with weak foundations. Its roots can grow through pavement, bricks or stonework, or creep into masonry cracks.
Japanese knotweed is widespread in Newtown and can be found on our roadsides, at Dickinson Park, Fairfield Hills, along the banks of the Pootatuck River, and in other cherished places. Check out the map below to see if knotweed has been found in your neighborhood; you can help us compile a more thorough inventory of knotweed by reporting your sightings below.
Let’s work together to reduce the spread of knotweed on town land and on our own properties.
Knotweed suppresses the growth of neighboring plants, alters soil chemistry, contributes to erosion and floods, and jeopardizes streambank stability. It reduces the number of aquatic macroinvertebrates, which are an integral part of the aquatic food chain.
Property damage caused by Japanese knotweed includes infiltration of structures with weak foundations. Its roots can grow through pavement, bricks or stonework, or creep into masonry cracks.
Japanese knotweed is widespread in Newtown and can be found on our roadsides, at Dickinson Park, Fairfield Hills, along the banks of the Pootatuck River, and in other cherished places. Check out the map below to see if knotweed has been found in your neighborhood; you can help us compile a more thorough inventory of knotweed by reporting your sightings below.
Let’s work together to reduce the spread of knotweed on town land and on our own properties.
Where is knotweed currently found in Newtown?
Frequently Asked Questions
What is Japanese knotweed? Japanese knotweed is an upright plant resembling bamboo that grows up to 10 feet tall. Its leaves are large and oval with pointed tips. Its small, greenish-white flower clusters can be easily spotted in August. The plant turns brown and dies back with frost. It grows rapidly and forms dense colonies.
Why is it a problem? Japanese knotweed spreads rapidly and will colonize an area, pushing out other vegetation. It grows so densely that nothing else can grow. Its roots produce allelopathic chemicals that prevent other plant species from growing or competing with it.
How did it get here? It was first brought to the U.S. in the late nineteenth century as an ornamental plant. With no native controls limiting its growth, it has become an invasive species here.
How does it spread? Most of the biomass of the plant is found underground in the plant’s stout rhizomes, which spread unseen and send up new plants. Even a small piece of the rhizome or a node from the plant can grow into a new plant. Pieces of rhizome can be moved by lawn mowers, transported by running water down a stream, spread by stalks and roots being composted and carried in dirt that is moved. It spreads VERY easily.
How can we get rid of it? The underground rhizomes of the plant must be killed. Annual applications of the herbicide glyphosate, applied by a licensed applicator, is the most effective method. It should be applied in the fall, after the knotweed flowers but before the first frost.
Why is it a problem? Japanese knotweed spreads rapidly and will colonize an area, pushing out other vegetation. It grows so densely that nothing else can grow. Its roots produce allelopathic chemicals that prevent other plant species from growing or competing with it.
How did it get here? It was first brought to the U.S. in the late nineteenth century as an ornamental plant. With no native controls limiting its growth, it has become an invasive species here.
How does it spread? Most of the biomass of the plant is found underground in the plant’s stout rhizomes, which spread unseen and send up new plants. Even a small piece of the rhizome or a node from the plant can grow into a new plant. Pieces of rhizome can be moved by lawn mowers, transported by running water down a stream, spread by stalks and roots being composted and carried in dirt that is moved. It spreads VERY easily.
How can we get rid of it? The underground rhizomes of the plant must be killed. Annual applications of the herbicide glyphosate, applied by a licensed applicator, is the most effective method. It should be applied in the fall, after the knotweed flowers but before the first frost.
What Japanese knotweed looks like around town
Resources about controlling Japanese knotweed
- Defeating Japanese Knotweed Along the Wild and Scenic Housatonic River in Connecticut
- 9 Common Mistakes To Avoid in Trying to Control Invasive Knotweed
- Optimising physiochemical control of invasive Japanese knotweed
- Preventing the Spread of Japanese Knotweed by the New Hampshire Department of Agriculture, Markets & Food
