Rare wildflowers show resilience in Lawrence park where city carelessly applied herbicide

Naturalist Ken Lassman shows the edible properties of Smooth Sumac on Nov. 1, 2024, at the Prairie Park remnant in Lawrence. The remnant was damaged by an erroneous application of broadleaf herbicide by Lawrence Parks and Recreation in April 2023. (Erin Socha for Kansas Reflector)

LAWRENCE — Each fall, Ken Lassman dons a thick pair of protective gloves and walks Lawrence’s Prairie Park remnant with a burlap sack, gathering seeds from the withering grasses and wildflowers.

This remnant, he explained, is around 9,500 years old — a rare example of old-growth prairie in a region that has lost more than 96% of its native habitat to development and farmland. The seeds he collects will be used to broaden the remnant’s footstep and battle the encroachment of woody and invasive plants.

Lassman, a naturalist who has written the Kaw Valley Almanac for 20 years, believes this special plot of land holds keys to navigating the environmental challenges of modern times.

“We don’t know what’s going to be important,” he said, “but we know something that has been here for 9,500 years might have a few lessons for our future.”

Ken Lassman shows the seeds he has collected from the Prairie Park remnant, which will be used to enlarge the remnant’s footstep and help the herbicide-damaged parcel find balance. (Erin Socha for Kansas Reflector)

The remnant, a 5-acre plot behind the Prairie Park Nature Center, suffered an enormous blow in 2023. In late April of that year, Lassman discovered rare wildflowers shriveled and dying, the result of an indiscriminate herbicide application by Lawrence Parks and Recreation. Public outcry was loud and swift, and the department eventually admitted its mistake.

Two growing seasons later, the remnant is showing resilience.

“There doesn’t appear to be any permanent loss of plant species at this time,” said Nathaniel Weickert, a researcher with the Kansas Biological Survey and Center for Ecological Research who has conducted surveys of the remnant.

A more thorough analysis of his data is forthcoming, but, he said, “I have a lot of hope for its recovery.”

While the worst-case scenario — the eradication of rare species — was not realized, the precarious ecological balance has shifted. The herbicide does not affect grasses, which already hold a competitive advantage in prairie ecosystems, instead targeting forbs — broadleaf flowering plants that include iconic prairie species such as sunflowers. Large populations of forbs were killed or damaged, making them more susceptible to disease, but the herbicide application was uneven and many were spared.

“It’s still a prairie, and there’s still diversity here, but it’s significantly changed the composition,” Lassman said. “Is this permanent? We won’t know until five, 10 years from now.”

The incident raised questions about Lawrence’s stewardship of natural spaces and its commitment to native plants more broadly. Native plants offer enormous environmental benefits, but the Lawrence city code still classifies many of them as noxious weeds.

“It’s worldview more than antagonism,” toward native plants, said Kelly Kindscher, a plant ecologist and ethnobotanist at the University of Kansas. The management of parks and recreation, he said, is oriented toward spaces like golf courses, and upper-level staff tend to have professional degrees in things like turf management.

Lassman said Kindscher was instrumental in securing protected status for the Prairie Park remnant in the late 1980s. Kindscher also persuaded the city to build the nature center next to the remnant rather than directly on it.

“There’s still this common thread — they have not had anyone with ecological or natural areas understanding throughout this whole period of time,” Kindscher said.

Incidents like the spraying of the remnant could have been avoided, he said, if the parks and recreation department had a staff member who prioritized conservation of natural spaces, or if the department contracted the maintenance of these spaces out to local conservation organizations.

“The specific management plan needs to be different” from other types of parks in the city, said Mark Hecker, assistant director of parks and recreation.

He said practices such as hand-removal of invasive plants, while necessary, are costly and time-consuming. The department, he said, has limited resources to contract out these practices.

Ken Lassman collects seeds on Nov. 1, 2024, from Lawrence’s Prairie Park remnant. The seeds will be used to broaden the prairie’s footstep. (Erin Socha for Kansas Reflector)

This past September, Lassman offered to train department staff on the removal of Sericea lespedeza, the invasive plant that was the intended target of the April 2023 herbicide. The plant was in the process of going to seed, he said, and while removal would not eliminate the problem, it would make an impact.

“To their credit, they came out,” Lassman said. “They had a crew out here for two days and they got almost all of it. And so, they’re trying.”

“What’s missing,” he continued, “is there is no comprehensive plan for managing this place in particular and also native plants in general. It’s just missing.”

Lassman sees efforts in neighboring Johnson County as a model. Johnson County Parks and Recreation implemented an extensive plan that prioritizes natural spaces and native plants, and even planted a prairie just to harvest seed.

There are people in the Lawrence community who could develop a plan if the city were willing, he said.

“That’s what is important in this whole ongoing thing,” Lassman said. “People do make mistakes, but the idea is to help them learn from them. There needs to be a comprehensive approach to managing their land to nurture native habitat in the city.”

Kindscher sees missed opportunities.

“Instead of this being a burden for the parks folks,” he said, “it should be this golden opportunity to showcase something.”