Road Dept. not letting knotweed get out of hand

The Berrien County Road Department has identified Japanese knotweed growing at the intersection of Snow Road and Mount Tabor Road in Oronoko Township, one of many locations throughout the county. Director Jason Latham said they started spraying the invasive plant this year, and will continue this year.

BENTON TOWNSHIP — A large stand of what appears to be the invasive Japanese knotweed is growing at the “Five Corners” intersection at Snow Road and Mount Tabor Road in Oronoko Township.

If allowed to continue, it could block the view of drivers at the crossroads. But if you try and cut it down, knotweed only gets worse.

How do you get rid of it, and who is responsible?

What’s up with that?

Berrien County Road Department Director Jason Latham said that the patch of knotweed at this intersection is one of many identified along the right-of-ways he is responsible for.

Latham has color-coded maps for each township that pinpoint the significant locations for knotweed, indicating which were sprayed with herbicides last year and which are to be targeted this year.

He said the spread of knotweed is “not horrible – but it’s certainly not good,” and his department is working to keep it from spreading.

“I understand that if it takes hold, you’re up a creek,” Latham said. “Our purpose is not to eradicate it, but to contain it.”

Japanese knotweed is a non-native plant first brought from Asia as an ornamental growth. The problem is that it grows very quickly, choking out other plants. It also has an extensive root system that can crack pavement, break water and sewer pipes and even damage building foundations.

It can be identified by its broad leaves, bamboo-like stems and white flowers that bloom in the fall.

Cutting it only spreads the seeds. It has to be treated with herbicides, and this can take several years. St. Joseph is in the middle of a multi-year program to eliminate knotweed from its ravines, where it has damaged sewer interceptor lines.

Latham said the road department spent about $8,000 last year with Dalton’s, a licensed chemical vegetation control company, to spray the knotweed. He said that this year’s spraying, which usually takes place in the fall when the flowers are out, will be more targeted, and they will continue to spray as needed.

The road department crews have been trained to identify Japanese knotweed and to avoid cutting it down when conducting roadside mowing, Latham said.

In situations where the spread could block the view at intersections, threatening safety, it will be cut back with the expectation that the patch will be sprayed later.

More manpower and money is needed to get rid of Japanese knotweed and other invasive species, Latham said. The road department hasn’t received any additional funding to fight off these plants.

It’s a big job. The Berrien County Road Department is responsible for 1,500 miles of roadway – adding up to 3,000 lane miles when counting both sides of the road.

Latham thinks that there needs to be a statewide program to get rid of the knotweed that is spreading all over Michigan.

The information on the location of knotweed has been given to the Berrien Conservation District, which applies for grants to pay for herbicide applications.

Residents who see what they suspect is Japanese knotweed can call the road department and put in a service request at 925-1196.

Contact:, 932-0360, Twitter: @HPMatuszak