By Penny Leuthard, Staff Writer

 

Like every other county in Minnesota, noxious weeds and terrestrial invasive species (an aggressive, non-native plant that outcompetes other species and causes harm to the environment, economy or human health), are a problem in Wright and Sherburne counties. 

 

Erik Heuring, weed inspector for Wright Co., works with the problem of these plants on a daily basis, and explained they are managed or eradicated depending on how they are categorized, as either prohibited, restricted or regulated. 

 

“In the 1990s, Canada thistle and field bindweed were a nightmare,” said Heuring. “They’re why the noxious weed law and list were started.”

 

Wild parsnip, Canada thistle, poison hemlock, oriental bittersweet and common teasel are prohibited weeds in Minnesota; in Wright Co., wild parsnip is on the eradicate list.

 

“There are little pockets of wild parsnip throughout Wright Co., including Clearwater,” said Heuring. “We’re instructed by the county commissioners to target it first and foremost, it’s priority number one.”

 

Poison hemlock, oriental bittersweet and common teasel are also on Minnesota’s prohibited eradicate list. 

 

“Oriental bittersweet grows extremely rapidly, and the weight of them can kill big trees,” said Heuring. “Common teasel, which is along the I-94 corridor, grows rosettes like a dandelion the first year, and then when conditions are right they grow six to eight feet high, flower and seed.”

 

Also on the prohibited eradicate list is palmer amaranth, a pigweed, which can grow up to eight feet tall. Native to the southwest U.S., it has slowly migrated north, and has been found in CRP (conservation reserve program) seed brought into the state. In a non-competitive environment, it can produce one million seeds.

 

“If you’re installing CRP, please buy from a reputable company,” said Heuring. “It can shade out crops and be so thick you can hardly get a combine through.”

 

Canada thistle is on the prohibited control list.

 

“Canada Thistle is more invasive and can spread rapidly,” he said. “It’s a biannual with deep roots. It flowers around the same time as Wild Parsnip, but because Wild Parsnip is priority, we generally bypass Canada Thistle until the fall.”

 

Purple loosestrife, another prohibited control species, is somewhat common and starting to get worse.

 

“It’s an aquatic species,” said Heuring. “Unfortunately, it’s pretty so people don’t report it.”

 

Also on the list are leafy spurge and spotted knapweed. Leafy spurge is found along roadsides, prairies, fields and other grassy areas. It’s deep-rooted, so it’s one of the hardest to control. Spotted knapweed is similar to Canada thistle, and can be found from Clearwater to Annandale. It flowers in July after Canada thistle, and likes gravely soil.

 

Heuring utilizes biological control when feasible. Along Hwy 24 for example, he releases weevils, which eat the seed head and root crown of spotted knapweed.

 

“It doesn’t eradicate, but it controls the problem,” he explained. “It also works for purple loosestrife and leafy spurge.”

 

If noxious weeds or terrestrial invasive species are found on private property, eradicating or controlling them is the responsibility of the land owner.  

 

Heuring recommends property owners visit the Minnesota Department of Agriculture (MDA) website at mda.state.mn.us/weedcontrol. The site has information on weeds and weed control, along with current noxious and invasive weed lists.

 

The University of Minnesota Extension office also has good information on their website, extension.umn.edu, including photos and descriptions of noxious weeds to help with identification.

 

For Wright Co. residents who have questions on weed control, emailing Heuring at wrightcoaginsp@gmail.com is the best way to contact him. Sherburne residents can get in touch with their extension office at mnext-sherburne@umn.edu, or by calling 763-765-3075.