Japanese knotweed is an invasive species that causes consternation throughout the region. (Provided photo — Nigel Mykura via Wikimedia Commons)

KEENE VALLEY — Each summer, the Adirondack Park Invasive Plant Program receives calls from landowners across the park who want to know how to manage invasive species on their property.

The most common question is, “How do I manage that ‘bamboo’?” Most often the plant in question is not bamboo; it is one of three species of knotweed that grow in the Adirondacks.

To help people learn how to identify these destructive invasive plants, prevent their spread, and manage infestations on their property, APIPP is hosting a free virtual learning event on Thursday, July 30 at 10 a.m. Visit www.adkinvasives.com/events to RSVP. APIPP also has a wealth of information about how to manage knotweed and other invasive plants on its website.

Each year APIPP staff and contractors also treat several hundred priority invasive-plant infestations that threaten ecologically sensitive public and private land.

APIPP’s knotweed treatment efforts will expand this year in a pilot collaboration with the former Regional Inlet Invasive Plant Program, founded by Inlet property owner Douglas Johnson. RIIPP was previously administered by the town of Inlet, and then by the Hamilton County Soil and Water Conservation District. The program grew beyond the district’s boundaries and was transferred to APIPP this summer. APIPP was able to assume oversight of the program because of the assistance provided by volunteer invasive plant coordinators. The coordinators identify areas with knotweed and seek landowner permission to manage the sites. APIPP then contracts with licensed applicators to treat the plants with herbicides.

“APIPP is honored to work with this group of dedicated, longtime volunteers to carry on the work started by Douglas Johnson,” said APIPP Manager Tammara Van Ryn.

Invasive knotweeds are fast-growing, herbaceous perennials originating from Asia and central Europe that form tall, dense, walls of growth. Knotweeds develop root-like systems called rhizomes that can spread up to 30 feet from the parent plant. Knotweed grows with such vigor that it is known to damage pavements, foundations and roadways, making it an important invasive species for residents to identify and remove.

“Riverbanks are particularly susceptible to damage from invasive knotweed,” said Emily-Bell Dinan, education and communications coordinator at APIPP. “Since knotweeds can regrow from many different plant parts, when stems or rhizomes break off from knotweeds upstream, a population can spread along an entire stream or river if gone unchecked.” Dense growth of knotweed makes the soils more prone to erosion, and knotweed-infested shorelines are more prone to flooding.

Funding for knotweed herbicide treatment for the 2020 pilot program comes from generous donors. Administrative support provided by APIPP is funded, in part, by the state Environmental Protection Fund, administered by the state Department of Environmental Conservation.