Water Chestnut has distinctive leaves which float on the water's surface in rosettes.

Water Chestnut Invades Cromwell

Water Chestnuts were found in a Cromwell inlet above Gildersleeve Island on the Connecticut River in July 2004. The sighting was reported to the DEP and pulled out of the inlet and disposed of. In late August, it was back again, and pulled out and displosed of by Larry and Pat. The DEP was notified of the pulling and continues to monitor this area, as well as any other areas where this invasive has been found. This annual species chokes water bodies making navigation impossible. Please report any other locations to the Connecticut DEP (860) 424-3034.

Trapa natans is not the edible water chestnut we buy in cans. Air bladders in stems allow leaf rosettes to float. Seeds are sharply-spiked with very hard shells, and can sprout after years of dormancy in the mud. It invades slow-moving water areas. If you see this invasive plant, please either notify the DEP immediately, and/or pull it (pull very slowly to allow roots to disengage from the mud) and dispose of it well away from any water body -- be sure to notify the DEP that you have done so (and where it was located).

In 2005, 2006, 2007, and 2008, a few stragglers were also removed by hand from the inlet. Overall, the eradication by hand-pulling seems to work extremely well. When pulling, tugging lightly and very slowly allows the mud to release the roots, and that helps eliminate re-growth.

Unfortunately, the same inlet is now becoming choked with Cabomba (invasive fanwort), as well as hosting most of the other invasive water weeds that plague our area including Asian milfoil and Curly-leaf pondweed. The Water Chestnut is the only invasive that is easily removed by hand, and the DEP has no funding to mechanically remove the other invasives, even though they are at least as much a threat as the Water Chestnut. The Cabomba volume has increased by at least double from 2007 to 2008.

This dried Water Chestnut shell measures 1.75 inch spike to spike. These are often found in flotsam along the CT River -- would be pretty nasty to step on barefooted. The empty shells float off once their plant has sprouted in the mud.

Giant Hogweed

Giant Hogweed (Heracleum mantegazzianum), an invasive, non- native plant confirmed in 2001 as a new state record (West Cornwall) continued to persist in 2002.

• Biennial or perennial herbaceous plant
• Habitat: riverbanks, disturbed sites
• Up to 15 feet in height
• Leaves up to 5 feet wide
• Hollow stems 2–4 inches in diameter
• White umbel-shaped inflorescence 2.5 feet across
• Seeds remain viable in soil for up to 7 years

CAUTIONS

• Sap causes large painful blisters
• Sap acts as anti-sunscreen
• Eye contact may result in blindness
• Displaces native vegetation

WHAT TO DO IF FOUND

• CONTACT Donna Ellis or the CT Invasive Plant Working Group to report location before removing.

• Avoid skin and eye contact with sap.
• Wear goggles, waterproof gloves, long sleeves
• Have several large plastic trash bags ready for disposing of flowers and seeds. Double or triple the bags to prevent ripping by plant stems.
• Use sharp serrated knife rather than motorized blades that may splatter sap on you
• Cut flowers first, and place in bags.
• Avoid shedding any seeds onto ground.
• Seal bags tightly and place in direct sunlight to solarize for at least 1 week.
• After solarization, put bags into garbage.

• Dig out roots and allow to dry before disposal. (For small plants and seedlings), or,
• Cut to ground level, cover with black plastic. Following year, check that plants don’t poke through, or
• Spray leaves with herbicide containing glyphosate (Roundup). Follow label directions (use in Summer). May take up to a week before plant begins to die.
• Repeat in 2 weeks if leaves are still green.
• Check plant site and surrounding areas for several (up to 7) years to monitor regrowth or germination.

Japanese Wharf Crab

Hemigrapsus sanguinius

This rather recent invader has only been in the U.S. about 15 years total. They're being tracked all along the Northern/Central East Coast. By reports, they are out-competing the Green Crab, which is sometimes labeled a native species, although the Green Crab may also be a non-native. Hemigrapsus lives in muddy rocky, or sandy rocky areas near the low tide line. Note that its body shape is different from our other local crabs. Hemigrapsus is square-backed, our other crabs are wide-backed, some, like the blue crab and sand crab, having pointy sides, some, like the rock crab having rounded sides. Fiddler crabs are more square than our other native crabs, but not nearly as square as Hemigrapsus.

The Green Crab is also a non-native species, but it's been here for more than 100 years.

Hemigrapsus Sanguinius

The Common Reed
Phragmites Communis

It has not been determined if this tall reed is truly native, or is an imported variant of our native reed, but the species has changed its behavior. It has become extremely invasive, taking over wet meadows and marshes which had been shorter salt marsh grasses.

Purple Loosestrife

This invasive species probably came into the U.S. as a garden species.It easily out-competes our native vegetation, turning swamps and wet meadows magenta with their flowers.Garden Loosestrife is a very similar garden species which is still sold in some area nurseries, and is still found in home flower gardens. It also is very invasive and should be avoided. If you find either species in your home garden, please destroy the plants. Liatris makes a good substitute. It's a vigorous grower, about the same height and close to the same color.