Invasive plants are plant species that are non-native or alien to an ecosystem, and are likely to cause environmental harm or harm to human health when introduced. When they begin to take root they will crowd out any native species living there, which can negatively impact the ecosystem depending on these native species. They are often found growing along riverbanks, and unfortunately the Farmington River is no exception to that. There are a number of invasive species known to grow alongside and within the river, including, Japanese Knotweed (Polygonum cuspidatum), Rock Snot (Didymosphenia geminata), and Asiatic Bittersweet (Celastrus orbiculatus). It is important to be able to recognize invasive species in our watershed in order to remove them from our homes and gardens, as well as educating friends, family, and neighbors on the issue.

With help from Connecticut Agricultural Experiment Station (CAES), Connecticut Department of Energy & Environmental Protection (CT DEEP), Farmington River Coordinating Committee (FRCC), Lower Farmington River and Salmon Brook Wild & Scenic (LFSWS) and many other partners, FRWA works both in and out of the water to help control the spread of a variety of invasive species. Learn more below about the different projects that FRWA has conducted.

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Terrestrial Invasive Species

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Japanese Knotweed

What is Japanese Knotweed?

Japanese Knotweed (Polygonum cuspidatum) is an invasive plant that originates from Japan, China, and Korea. It was first brought to the UK from Japan in 1825 as an ornamental, and from there was brought to the US in the late 19th century. The plant itself is rapidly spreading, and is able to thrive and grow in a number of habitats and conditions. It prefers areas with plenty of sunlight, which are usually areas with high human activity as well as streambanks and wetlands. It is identifiable by its large, shovel shaped leaves and clusters of white or cream colored flowers. Japanese Knotweed is also known to grow quite tall, usually between 7 and 10 feet, and becomes very dense quite rapidly. It is widespread throughout the Farmington River Watershed, both on streambanks and further inland.

Why is it problematic?

Japanese Knotweed grows as a very tall thicket, making it difficult for wildlife or people to control. It is nearly impossible for wildlife to feed on it or trample it, which promotes the further spread of it. The roots are also incredibly hardy, which makes pulling up all of the roots and rhizomes extremely difficult. Along with being difficult to remove, it will also shade out any native plants around it, because it can grow so tall and dense. This in turn can also reduce native wildlife populations that may depend on these native plants for habitat or food source. Knotweed will also cause the soil to destabilize, usually along banks and streams, which will lead to erosion as any loose soil will wash away with any major rain or snow event.

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Asiatic Bittersweet

What is Asiatic Bittersweet?

Asiatic or Oriental Bittersweet (Celastrus orbiculatus) is an invasive plant that originates from East Asia, and was brought to the US in the late 1800’s as an ornamental. It is easily identifiable by its woody vines and round leaves, as well as red-orange pea-sized fruit that grow in the fall and persist throughout the winter. It grows rapidly and climbs trees and other foliage, and can reach lengths of over 60 feet. While it is more productive with moist soil and plenty of sunlight, it is also very shade tolerant and has been found growing in a number of habitats, such as; forests, fields, beaches, dunes, and forest edges. It is extremely aggressive, and is found all over the Farmington River watershed.

Why is it problematic?

Asiatic Bittersweet chokes out native foliage by wrapping around and strangling the stems and trunks. In some instances, it will form huge blankets of thick, branch-like vines throughout a stretch of woodlands, which can effectively kill all the trees it wrapped around. It is also very easily spread, with a seed germination rate of 90%. Each plant will have about 350 fruits, and each fruit has 3 - 6 seeds inside. It is typically spread by birds or other wildlife eating the fruit and dropping the seeds. People also may be spreading the seeds unknowingly by picking the fruit or trying to trim it back, while leaving the fruit behind. Bittersweet is also capable of reproducing asexually, as the roots, root fragments, root crown, and runners are all able to sprout.

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Japanese Barberry

What is Japanese Barberry?

Japanese Barberry (Berberis thunbergii) is an invasive plant that originates in China and Japan, and was brought to the US as an ornamental in the 1860s. It grows as a shrub, usually between 3 and 7 feet in height, and will become compact and dense if not pruned. Its leaves may vary in shape due to habitat and soil condition, but are typically oval shaped and will grow in small clusters. Barberry also has thin spines which will grow below clusters of leaves. Another notable feature is the small, bright red fruit that grows in the fall and remains on the plant into the winter. It is capable of growing in a number of spaces once established, but will prefer sunny spaces with moist, well draining soils. It has effectively invaded a number of spaces, such as open woods, fields, roadsides, and natural paths. Barberry is also thought to harbor black-legged ticks, which are known carriers of Lyme disease. 

Why is it problematic?

Japanese Barberry exhibits a number of invasive traits, making it a problematic species in the area. It produces a high number of seeds with a good germination rate, estimated to be up to 90%. Birds and other wildlife will pick and eat the fruit and drop the seeds, which contributes to the spread of it. Since it grows very dense, and is typically avoided by grazers or predators, it can outcompete other native plants in the area. This reduces food sources and habitats for local wildlife. There have also been cases of Japanese Barberry causing changes in the pH of the soil, along with other biological activity occurring in the soils. This will also alter how native foliage will grow in an area. Barberry is also a human health hazard, as it is thought to harbor black-legged ticks, which are known carriers of Lyme disease

Aquatic Invasive Species

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Water Chestnuts

What are water chestnuts?

The water chestnut is a rooted, floating aquatic plant. It was originally brought to the United States from Asia for horticultural purposes in the 19th century. Soon after introduction, Asa Gray, of Harvard University had purposefully planted Water Chestnuts in ponds near the Sudbury and Concord Rivers. By 1879, the plant started growing in the Charles River. It has continued to spread all along the east coast as far south as Virginia and Kentucky and as far north as Quebec. Of course, it has also began to infest the Connecticut River causing it to be categorized as an invasive species in the Connecticut River Watershed.

Why are they problematic?

Water chestnut plants create nearly impenetrable mats across wide areas of water, limiting the passage of light. As the water chestnut plant decomposes, it decreases dissolved oxygen in the water that fish and other aquatic life need to survive. This invasive plant hogs space and nutrients from native plants, many of which are food sources for native animals, causing a complete disruption of the ecosystem as a whole. Water chestnut mats, reaching 16 feet deep, can also restrict recreational activities such as swimming, fishing, and boating. The spiky seed of the water chestnut plant may also cause injury to humans and wildlife upon touch.

Why is our work important?

Each water chestnut plant has 15 - 20 rosettes, and each rosette can generate up to 20 seeds yearly. Additionally, the seeds produced by these rosettes are viable for up to 12 years, making it even more difficult to fully remove. Therefore, it is important to stay educated on the dangers of these invasive plants. Furthermore, holding consistent clean-ups in the infested waters will enable our waterways to continue to provide essential services to our community, along with property composting these invasives to reduce the risk of spreading. FRWA would not be able to do what they do without the help of volunteers throughout the community. With help from volunteers from FRWA itself, Knox Hartford, Connecticut River Conservancy, Metacomet Tours, Perkatory Coffee Roasters, and many other amazing organizations, FRWA is able to make meaningful progress toward cleaning up the affected bodies of water one step at a time.

Rock Snot

What is Rock Snot?

Rock Snot, or Didymo, is a species of algae which will ‘bloom’ and form large cotton-like mats of material on stream bottoms. Its appearance and texture resembles wet wool or cotton on rocky streambeds, and will be tan or brown in color. It is typically found in areas with moderate to high flow, relatively shallow waters, and with plenty of sunshine. Rock Snot thrives in waters that are low in nutrients, high in dissolved oxygen, and cold temperatures. In Connecticut, there are three species of Rock Snot; Didymosphenia geminata, Didymosphenia hullii, and Cymbella janischii. Both species of Didymo are found in the West Branch Farmington River, and have not been found any lower than the Sandy Brook confluence in Barkhamsted. These species will typically bloom from December to May, and prefer cold water. C. janischii is also found throughout the West Branch Farmington River, and is known to bloom between June and August. This species also thrives in cold waters, but is a bit more tolerable of slightly warmer waters than the other two species. It is assumed that Rock Snot was brought into the Farmington River watershed by anglers wearing or using equipment that previously was in contact with it in other waters. 

Why is it problematic?

Larger blooms can result in more extensive coverage of the stream bottom, which causes native plants and insects to be smothered, in turn affecting the entire food chain. This especially affects the trout populations, who live in colder waters, along with other fish species. Rock snot may also cause lures to become tangled, and makes it much more slippery to walk in the stream. It is important to understand that Rock Snot is very easy to transmit to other waters unknowingly. The microscopic cells can cling to fishing gear, boats, and even your pets and will remain viable as long as it has any amount of moisture to sustain it. If you suspect you came into contact with it, disinfect any affected equipment with a 1:9 solution of bleach and water, and then allow it to dry completely for at least 48 hours before entering new waters.

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What can be done to help slow the spread?

Following the "Clean, Drain, Dry" method to prevent further spread of aquatic invasives!

Clean off all plants, animals, fish, mud and other debris from your boat and equipment before leaving the launch. It is very important not to bring anything home with you! Check all parts of your boat that are in contact with the water, and ensure any waders, boots, kayaks, fishing equipment, and pets are completely rinsed off.

Drain all water from your boat and other equipment used before leaving the launch site. Equipment includes waders, bait buckets, canoes, kayaks, boots, ballast tanks, etc.

Dry any and all equipment that came into contact with the water before entering new waters. Drying times should be one week during dry/hot weather, and up to four weeks during cool/wet weather. If drying out equipment is not possible, there are other disinfection methods that can be used, such as washing with hot pressurized water, freezing for at least 24 hours to kill all of the cells, using a 1% salt solution prior to rinsing, or using a 1:9 bleach solution before allowing to dry at least two days.

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Hemlock Wooly Adelgid (HWA)

What is HWA and why is it problematic?

The Peoples and American Legion State Forests are extensive watershed forests bordering the upper Farmington River and are essential for natural diversity, wildlife, and recreation. These forests have a large eastern hemlock component, critical for wildlife habitat, thermoregulation, and the filtration of streams that feed into the main river. The Hemlock Woolly Adelgid (HWA) is an invasive insect that has been infesting Hemlock trees in the State of Connecticut since the ‘90s. For 28 years, the State of Connecticut with the CT Agricultural Experiment Station, has been releasing Sasajiscymus tsugae, a beetle that predates exclusively on HWA. It is through this biological control that the infested trees form a symbiotic relationship with the aphid-like creatures to control this invasive pest. In recent years, however, many native hemlocks, including the Eastern Hemlock, have become heavily infested with HWA. Due to climate change, forests have also been subject to months of severe drought in the summer of 2020, an abnormally dry spring in 2021, and an extreme summer drought in 2022, creating stressful conditions for moisture-loving hemlocks.

What work has been done so far?

Biological control with S. tsugae to reduce HWA pressure and impacts appear to have significantly helped hemlocks survive and initiate recovery.  Recovery has been seen 5 –18 months after beetles were released, despite other significant stressors such as the drought. Therefore, the FRCC has been working closely with Dr. Carole Cheah, Research Entomologist with the CT Agricultural Experiment Station, to continue control efforts of the HWA through the release of S. tsugae, over the past few years In May of 2022, with funding from the FRCC, 5,050 beetles were released on infested hemlocks along the upper Farmington River at the American Legion and Peoples State Forests, with the help of volunteers from the FRCC, Friends of the American Legion and Peoples State Forests (FALPS), and staff from the CT DEEP Forestry Division. Most recently, the FRCC also funded the release of beetles on June 4th, 2023 at Pratt Place, Canton Land Trust property, and in American Legion and Peoples State Forest on June 6th, 2023. LFSWS joined this effort in 2023, focusing on State and Town-owned property in the lower Farmington River area.

How can you help?

1. Inform us if you spot invasive plants at any locations within the Farmington River water shed. 
2. Make sure to clean your boat, fishing gear, waders, or shoes if you have come in contact with invasive plants.
3. Join us for volunteer invasive plant removal work days! Stay informed here.

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