Native Plants to Replace Cattails at Humboldt Park Lagoon
September 20, 2018 | Topics: Stories
By Katherine Keller
Members of the volunteer Humboldt Park Friends have taken on an ambitious project to improve Humboldt Park Lagoon water quality and replace invasive cattails with native plants.
Working with Milwaukee County Parks staff, members of the HPF Lagoon Restoration Committee created a pilot program to address the cattails and improve water quality.
The pilot is designed to test and confirm methods to remove cattails, prevent or minimize their regeneration, and replace them with beneficial native plants.
Cattails were introduced by Milwaukee County Parks about 15 years ago to deter geese from accessing the lagoon from the shoreline. They thrived, and although originally planted in only a few areas, they spread and now cover about 90 percent of the shoreline. In some areas, they extend 40 feet into the lagoon, choking out native plant species.
Additionally, because they grow as tall as nine feet or more, they block park visitors’ view of the lagoon.
To cull the invasive plants, cattails are cut below the water level, which kills them by depriving them of oxygen. The first cutting was performed in Fall 2017 and it will be repeated this fall. HPF members monitor the test area watching for the reemergence of cattails in the spring and summer. For those growing in the soil along the shore, the volunteers attempted to dig them up and remove the roots.
“Some new cattails are growing (back) from roots we didn’t completely remove on the shore,” said Patrick McSweeney, a member of the restoration committee. “The cattails we cut below the waterline last fall appears to be a method successful in halting the spread of these plants.”
Removing cattails will be an annual process until they’re eradicated.
To date, members of Humboldt Park Friends and other volunteers cleared cattails and other invasive plants from two small sections of the four-acre lagoon’s shoreline.
Native species were planted in the two test areas in an effort to control erosion and maintain the new unimpeded lagoon sightlines. A total of 169 plants were planted
on June 9.
Committee member Joanna Demas, an environmental educator and land manager for the River Revitalization Foundation, selected the plants that HPF purchased from Johnson’s Nursery in Menomonee Falls and Marshland Transplant Aquatic Nursery in Berlin, Wis.
HPF hopes that the native plants will thrive and help prevent excessive nutrients from migrating to the lagoon. Grass clippings, goose and other animal feces, dirt, and other materials that collect on the paved pathway are common culprits that contribute the nutrients.
“After a month, things look very promising and additional clearing and planting is planned for late summer/early fall,” said McSweeney.
“Based on what we learn through the pilot project, public input, and from engaging professionals, we can develop a cost-effective plan that can improve the water quality, habitat, beauty and access to the lagoon,” said McSweeney, a member of the restoration committee.
Milwaukee Riverkeeper will test water quality and establish a benchmark that will also provide guidance about what actions need to be taken to clean the water.
The restoration pilot is supported by a $4,010 grant from the Southeastern Wisconsin Watersheds Trust (Sweet Water). Humboldt Park Friends, a nonprofit volunteer group, was one of 14 groups that received a Sweet Water grant this year. HPF received the first half of its grant during the annual Clean Rivers, Clean Lakes conference at Alverno College on April 26. It will receive the remainder after the shoreline planting is completed this summer.
McSweeney said that HFP has spent about a quarter of the grant money, “being very thrifty,” purchasing shovels, rakes, cutting shears, waders, as well as fencing, posts, mulch, and dumpster rental, in addition to the plants. “We’ll purchase more plants and supplies for the additional work this fall and are working with Sweet Water to dedicate the funds toward the other work being planned,” he said.
Results from the cattail removal and replanting with native species pilot will be used in development of a long-term lagoon restoration and maintenance practices plan. A complete restoration of the lagoon could be achieved after a few years following the pilot tests, in a best-case scenario, McSweeney said. But much depends on funding.
HPF anticipates that costs for a full restoration will be paid by a private/public partnership with a combination of county funds, private donations, and grants and gifts from foundations or corporations.
“We don’t have a cost estimate at this point because of a number of variables. But we know it won’t be cheap. This is a long-term project that involves not only aesthetics and historic elements, but also is dependent on public interaction and support,” McSweeney said.
The selected natives that the volunteers planted are Golden Alexander, Great blue lobelia, Blue flag iris, Sweetflag, Arrowhead, Pickerelweed, Path rush , Lake sedge, Ohio spiderwort , Blue vervain , New England aster, Swamp milkweed, Blue joint grass, Porcupine sedge, Fox sedge, Tussocks sedge, Turtlehead, Obedient plant, Marsh blazing star, Monkey flower, and Prairie dock.
The pilot project is expected to last several years in order to test and confirm the effectiveness of the cattail/invasive species removal method. To date, HPF is encouraged by the results.
“What we learn from this will help determine long-term actions. Our next steps are to work with the County Parks Department to develop short-term and long-term projects to continue the momentum we’re establishing,” said McSweeney. “We’ll be clearing more cattails later this summer or early fall and replanting additional shoreline areas. We’ll need neighborhood volunteers to accomplish that. And then in November, we’ll hold a public meeting to update our residents on what we’ve done and seek community input to move the process forward.
“This is the first step of a marathon. There is a lot of work ahead for the Humboldt Park Lagoon.”
The lagoon was created 125 years ago by dredging wetlands.
Active members of the Humboldt Park Friends Lagoon Restoration Committee are Tim Richter, Jane Le Capitaine, Joanna Demas, Greg Stilin, Collin Smith, and Patrick McSweeney. Additionally, a number of local residents have been involved in park cleanups, plantings, cattail removal, public meetings, and other activities.
Additional cattail and invasive vegetation removal and shoreline restoration are planned for early October. To learn more or get involved, consult humboldtparkmilwaukee.org.
This story was first published in Bay View Compass on July 31, 2018. Reprinted with permission.