Japanese knotweed threatens Michigan rights-of-way

Japanese knotweed was the “it” plant to have 150 years ago and was cultivated at many estates in the US.  Brought from Japan, China and Korea, it didn’t take very long for US. residents to realize that knotweed was more foe than friend.

Today, Japanese knotweed has become a notorious invasive species, according to the Summer 2018 edition of Crossroads, the quarterly journal of the County Road Association (CRA) of Michigan.

“When I first saw it on an abandoned property, I didn’t know what it was,” said Hannah Hudson, former grass and weeds inspector for the City of Kalamazoo and current independent Japanese knotweed specialist and consultant. “I began researching it when a resident called and said they had been battling this plant in their alleyway for years. Whole countries are trying to fight this stuff.”

Invasive species, such as Japanese knotweed, are posing serious threats to Michigan roadways, prompting county road agencies to establish collaborative efforts to fend them off.

Invasive species vary across the state, but their effects are similar. They disrupt local ecosystems, take over rights-of-way and destroy roads from the bottom up.

There are an estimated 33 species of invasive plants in Oakland County alone, according to Brad Knight, environmental concerns coordinator with the Road Commission for Oakland County.

“We have invasive species originating from Europe to Japan, all growing differently requiring different methods of eradication, but all destroying property and affecting the safety of Oakland’s road system,” Knight said.

With so many types of invasive species, all requiring different treatments and control methods, Oakland County established a Cooperative Invasive Species Management Area (CISMA) in 2014, which includes almost 30 community agencies, to coordinate invasive species efforts.

By creating and utilizing CISMAs funding options like grants through partnerships, road agencies are beginning to employ wide-scale techniques to combat the growth of invasive species.

The 83 members of the County Road Association of Michigan represent the unified voice for a safe and efficient county transportation infrastructure system in Michigan, including appropriate stewardship of the public’s right-of-way in rural and urban Michigan.

Collectively, Michigan’s county road agencies manage 75 percent of all roads in the state, including 90,000 miles of roads and 5,700 bridges.

County road agencies also maintain the state’s highway system in 64 counties.

Michigan has the nation’s fourth-largest local road system.