Knotweed a growing problem in Saratoga County
SARATOGA SPRINGS, N.Y. » A rapidly expanding invasive plant is wreaking economic and environmental havoc in Saratoga County.
Japanese knotweed can damage sidewalks, foundations and water lines, and causes streambank erosion that seriously impacts fishing, kayaking and related activities on waterways such as Kaydeross Creek.
Laurel Gailor, of Capital Mohawk PRISM (Partnership for Regional Invasive Species Management), discussed such threats during a recent program at Skidmore College.
“It can really affect property values,” she said. “It can deter people from buying. One woman told me she looked at a house in Saratoga Springs and pulled her offer off the table because she saw knotweed growing on the property.”
Knotweed, which may grow 15 feet high, first came to the U.S. from Asia in the 1890s when it was used as packing material for overseas shipping. Like many invasives, it has grown steadily over time and has now become quite problematic.
Japanese knotweed is found in 42 states coast to coast except the arid Southwest, several of the Deep South Gulf states and the highest of the Rocky
Mountains. It is also in eight Canadian Provinces.
It’s commonly found along streams and rivers and quite often it’s moved by high water. Pieces carried downstream take hold and soon begin to spread. Many areas along the Kaydeross are lined with knotweed, which has a white flower, Gailor said.
Worst of all, the plant is extremely difficult to eradicate. Rhizomes, or roots, have an extensive underground network. So chopping the plant down does no good and can make matters worse because even tiny pieces may take hold without proper disposal.
Digging, “solarzing” and treating with chemicals are the three most common ways to combat knotweed, Gailor said.
However, digging requires heavy equipment to fully remove roots, at least eight to 10 feet deep. Material should be burned before filling the pit back in.
To “solarize” knotweed, plants should be placed on a large tarp and covered with black plastic in a sunny spot, which “cooks” and kills knotweed. This natural disposal method takes several months. Plants covered in early summer may take until autumn to break down and decompose.
The most effective method, approved by The Nature Conservancy, is the use of herbicides. But this should only be done by a license, trained applicator. This technique is used for eradicating large areas, Gailor said.
A list of applicators is available from PRISM.
People should be extremely careful not to put knotweed with lawn trimmings and yard waste that goes to a municipal composting facility because the plant can take hold and spread there.
Capital Mohawk PRISM is one of eight PRISM organizations set up around the state to deal with problems related to invasive species.
For more information, call (518) 885-8995 or go to www.capitalmohawkprism.org
Japanese knotweed is extremely difficult to eradicate once it takes hold.
Japanese knotweed is an invasive species that has serious environmental and economic impacts.