Central College News

Featured: No Parking on the Prairie

September 25, 2012

Students weed the prairie bioswales in a campus parking lot to showcase the fall wildflowers that reduce toxic run-off.


Mary Stark’s Reading and Writing Strategies class and Intersections class joined Russ Benedict’s upper-level Conservation Biology/Ecology of Iowa class to weed and maintain the prairie bioswales in the parking lot across from Central Hall. Both of Stark’s courses for first-year students have a sustainability component.


Iowa was originally 70-85 percent prairie. Today, less than one percent of that prairie remains. People like Russ Benedict are working to restore prairie habitats across the state.

Prairie is a slow-growing ecosystem. Russ Benedict says that many people find prairie gardens to be ugly in the first few years, especially when they become choked with weeds. Benedict’s and Stark’s classes worked to remove mare’s tail, a native weed that has taken root in the bioswales in the parking lot. “I have nothing against this particular plant,” says Benedict, “but we want to show off the prairie grasses underneath.”

The gardens in the Central Hall parking lot were planted last fall with native ecotype seeds. Not only are the plants native to Iowa, but the seeds originally came from the area around Pella.

Although they are often referred to as rain gardens, these trenches are actually bioswales. Rain from the parking lot is funneled through indents in the curb down into the garden. The plants and soil absorb most of the water; the rest runs into a pipe connected to the sewer system. The rainwater trickles slowly into local streams rather than rushing in all at once during a downpour.


Back in 1830, as the first European settlers were arriving in Iowa, prairies absorbed 90 percent of rainfall; the last 10 percent was funneled into streams and rivers. Today, prairie has been replaced by impermeable surfaces like concrete and sunbaked farmland. Now, 50 percent of precipitation runs into nearby streams, eroding them at a much higher rate. Chemicals from lawn care, agriculture and vehicle pollution end up in the streams, as well.

“How many of you knew something about tallgrass prairie a month ago?” Benedict asks a group of first-year students. “How many of you could name even a few of the major plants in a prairie?” No hands go up. Very few people know much about the original habitat of  Iowa.

Russ Benedict says the bioswales on campus serve a dual purpose: limiting run-off and educating people about the prairie. “We are giving students places to learn,” says Benedict of the parking lot bioswales and the prairie garden near Weller Center.

Benedict used a weed-eater to cut down the bigger mare’s tail specimens, while students pulled out the smaller ones by the roots.

Students gathered the mare’s tail in a truck that later dumped the vegetation in the off-campus compost heap. The wrestlers in Mary Stark’s class took particular joy in stamping down the weeds to make more space.

Mary Stark’s capstone class, LAS 410, worked with Russ Benedict cleaning up the bioswales on Sept. 20. The 11 seniors, who are studying science, history, literature and service in the capstone, finished one-fourth of the total weeding before the freshman took over the next week.

One-third of the North American continent was originally tallgrass prairie.

“It’s all about plant competition,” says Mary Stark, pointing out rough blazing star that now has room to grow.

The most common prairie species in the bioswales include big bluestem, switchgrass, Indian Grass, little bluestem and sky blue aster. Showy goldenrod and fall sunflowers, pictured here, are two of the most beautiful.

This superb example of rough blazing star was uncovered when the mare’s tail choking the bioswales was removed.

Prairies are incredibly diverse places. More than 30 species are planted in the small designated areas in the parking lot. Benedict says a prairie the size of Central’s campus would have 300-400 different plant species.

Russ Benedict has a particular interest in tallgrass prairie. His Prairie Restoration Project aims to determine what mixture of prairie species is the “magic number” to plant on unfarmable land around Iowa. Benedict and students planted test plots at the Carlson-Kuyper Field Station last spring.

Two years from now, the bioswales won’t need as much weeding because the prairie plants will choke out the mare’s tail that is taking over now.

After the beautification effort, Mary Stark received emails from people all over campus complimenting the now-visible wildflowers. “That’s what is great about a place like Central: students and faculty working together on a project that helps the campus look great for all,” said one grateful employee.