More Than Just Flowers Decorate the Gardens at This Clean-Water Plant

Operators at a central Wisconsin municipal water and wastewater utility plant flower gardens to help monarch butterflies breed new generations.

More Than Just Flowers Decorate the Gardens at This Clean-Water Plant

Thanks to plant operators and staff, part of an otherwise unusable piece of land at the Marshfield (Wisconsin) Wastewater Treatment Facility adds beauty and provides much needed habitat for the declining populations of monarch butterflies.

Surrounding the circular ends of two 400-foot-long concrete oxidation ditches, nearly half an acre of land was converted into a garden of wildflowers and native grasses. More than 20 species of wildflowers such as black-eyed Susans, wild bergamot, yellow coneflower, joe-pye weed and swamp milkweed create an area pleasant to the eye and attractive to monarchs.

“It was a wasted end of the oxidation ditch that was hard to mow,” says Sam Warp, plant superintendent in Marshfield. “Weeds had taken over the area, and so it wasn’t a very good use of the property.”


Warp and his staff first prepared the area by removing brush, grass and weeds. Soil amendments were added to condition the seedbed for planting. In 2018, the wastewater and water treatment plant staffs planted the wildflower seeds, plants and native grasses. “It actually flowered a little bit the first year, so we were really happy,” Warp says. “When you are rebuilding a wild prairie, it’s a five-year project until you get what you’re hoping for.”

Since 2018, an area surrounding the sign in front of the wastewater plant has been converted into a wildflower garden. Warp says that each year, the plant teams look for a different area that can be made into a wildflower garden to attract monarchs. Last year, a garden was also created at Griese Park, a city attraction with a nature trail, picnic areas and shelters.

“When you get the garden just right and the flowers that come up first are blooming, it looks fantastic,” Warp says. “But the rest of the time it looks like native weeds because they’re still growing.”


The original wildflower garden resulted from a partnership in 2017 between the wastewater and water treatment divisions of Marshfield Utilities to create a monarch conservation project. “I belong to Friends of Mill Creek, a grassroots community group committed to improving the water quality of Mill Creek, which is our plant’s receiving stream,” Warp says.

“Several members of that group share my interest in wildflower prairie restoration and asked me to find a partner for the conservation project. Because the wastewater plant seemed like the ideal location, Marshfield Utilities supported the idea.”

Warp’s interest in monarch butterfly habitat and wildflowers is not accidental. For more than 25 years, he has practiced his hobby of gathering the butterfly eggs from milkweed plants each spring and summer and nurturing them at his home through the larvae and pupa stages. He then releases the adult monarchs.

“Last year we fed about a hundred, but usually we feed around fifty,” Warp says. “If you do too many, it starts to seem like work rather than a hobby.” Warp’s interest in butterflies is in line with his participation in other environmental groups, such as the Marshfield Groundwater Guardians a program promoted by the national Groundwater Foundation.


Twice a year, members of the utility partnership team up to maintain the butterfly gardens. They set up a day in spring and fall to weed, add mulch and replace dead flowers or plants. The New England aster is emphasized as a replacement because it’s a late-season bloomer that provides nectar for pollinators, especially the monarchs before their migration to Mexico.

“We also plant lots of milkweed because even though they feed on the nectar of many flowers, they breed only where the milkweed is found,” Warp says.

The original garden has been designated as a Certified Wildlife Habitat through the National Wildlife Federation. It is now part of the Million Pollinator Garden Challenge, a national effort to create a million gardens that provide habitat for declining pollinator insects, like butterflies and bees.

“We actually get people who come by and if they see weeds, they’ll take them out,” Warp says. “Once they see how nice it is, the citizens buy in and see that it’s a good thing. That was the goal, and it has worked better than we ever thought.”

Warp says that when the black-eyed Susans are blooming, the gardens look really impressive, even though it only lasts for about a month. “It’s like, wow! Now that’s why we did all that work. Next year we might target the water field. That’s where city’s water wells are located, and it has nice paved walking path that lots of people use.”  


Comments on this site are submitted by users and are not endorsed by nor do they reflect the views or opinions of COLE Publishing, Inc. Comments are moderated before being posted.