For 27 years, Jim Nicholas of Minneapolis was a data analyst with the Minnesota Hospital Association. After retiring in 2016, he chose a decidedly different path:

Buckthorn buster on a bicycle.

For the past five years, 74-year-old Nicholas has become legendary along the paths of Lake Harriet in southwest Minneapolis, easy to spot with his red suspenders, thick yellow gloves, wide-brimmed hat and bike trailer, edging himself upward into prickly spots on various hills to cut-cut-cut away.

One resident, writing to this very newspaper, described Nicholas as an "eccentric fellow" who deserved public praise.

Curious strollers stop to ask him what in the world he's doing. Others seek his advice about the invasive buckthorn in their own yards.

And at least three people have called the police on him.

"I carry a sign that says 'invasive species removal,' and that gives me some cover," Nicholas said.

Nicholas volunteers about 10 hours a week busting buckthorn. "I treat it like a part-time job," said the married father of two young adults.

"I have to rest in between. It doesn't look like the hill is that steep, but you kind of have to pull yourself up."

Nicholas began to grasp the buckthorn "problem" during his work years, when he rode his bike to and from his job in St. Paul, 9 ½ miles each way.

"I had a perfect route," he said. "I took [Minnehaha] Creek to the Mississippi, across the Lake Street bridge and then it was a short hop to where I worked. The buckthorn permeated every part of the Grand Rounds Trail."

He describes buckthorn "as the poster child for invasive species."

It's found in two-thirds of Minnesota counties. The Minnesota Department of Natural Resources website describes two kinds of buckthorn: common, also called European, and glossy. Both were brought here from Europe as a popular hedging material.

The plants create many problems, such as out-competing native plants for nutrients, light and moisture; degrading wildlife habitat, and threatening the future of forests, wetlands, prairies and other natural habitat.

Plus, they create a mess.

"Birds like robins eat the buckthorn, which is like a laxative, and excrete it all over the place," Nicholas noted. Efforts to rid our state of buckthorn began in the 1980s.

Before retiring, Nicholas participated in a few "buckthorn busts," sponsored by the environmental committee of the Lynnhurst Neighborhood Association. After retiring, he became a park steward.

Every week, split into two or three day shifts, the Minneapolis man hops on his bike, pulls his trailer along Lake Harriet pathways, picks his spots and treks up 50 or 100 feet.

It's dicey work.

"The common buckthorn has sharp, spiky stems," Nicholas said. "I have to wear a canvas shirt and gloves. In the winters, it's best that you have on a couple layers, eye protection, something to cover your head. It can get thick enough that you wouldn't want to walk through it."

Little wonder he largely works alone.

"All are welcome, but not very many have answered the call," he said with a boisterous laugh.

He understands. "It's actually just not that much fun," he said. "But there is satisfaction in it. You cut a tree, prune it, drag it …"

Sometimes, members of scout troops or other service organizations join in "and that's a lot livelier," he said.

"Everybody is happy for three hours and you feel good, and you should feel good."

His wife, Anita Manne, and daughter, Emily, often walk past him and wave. Anita, he said, calls his effort "admirable."

"But they don't hang around," he said.

At least three times, he's had to pull out his identification card for police who have been called about his seemingly strange adventures. One "adamant" woman insisted that the birds "enjoyed the buckthorn," and Nicholas was cheating them of their happiness.

"Show me your science and I'll listen," she said.

"I copied some articles and presented them to her," he said. "To this day, she ignores me. I still say hi when I see her."

Cutting down buckthorn isn't his only concern. Re-establishing native plants in the buckthorn's place is crucial. Nicholas has a designated plot along the Minnehaha Creek bike path where he planted buckthorn seeds last spring, with native grasses and shrubs adjacent. His hope is that native plants will suppress the regrowth of buckthorn.

He'll eventually report back to the University of Minnesota's Invasive Terrestrial Plants and Pests Center on whether his effort succeeded.

Nicholas is joined in his effort by Brian Crotteau, a fellow Minneapolis volunteer whom Nicholas describes as "younger and stronger."

Crotteau, 54, has won three grants from his employer, Medtronic, to experiment with native plant restoration where buckthorn now flourishes. "If we don't protect these areas, they'll disappear," he said.

Crotteau noted that "dozens and dozens" of volunteers have heeded the buckthorn call, but he's especially appreciative of Nicholas. "Jim is so diligent, hardworking, honest, trustworthy," Crotteau said. "He's a great advocate and citizen."

Plus, he noted, the two men have a shared superpower: "We can spot buckthorn a mile away."

Gail Rosenblum • 612-673-7350

@grosenblum