Honeysuckle Warriors Battle Plant Invaders

In 2012, Lilly Global Day of Service volunteers removed invasive plants to open up views of Fall Creek and its bridges and banks. KIB photo.

by Katie Grieze

Just because something’s green doesn’t mean it’s necessarily good, says Rebecca Dolan, who retired in 2018 as director of the Friesner Herbarium at Butler University. Some plants invade areas in harmful ways, driving out native species that are essential to healthy, diverse ecosystems. One major culprit hides behind a guise of sweet-smelling innocence: Amur bush honeysuckle.

Back in the 1950s, the flower-and-berry-covered shrub was introduced throughout Midwestern urban areas, promoted by the United States Department of Agriculture Soil Conservation Service (now known as the Natural Resources Conservation Service) as a beneficial plant that would grow quickly, help stabilize soil, and reduce erosion.

“But it turns out that it spreads too quickly,” Dolan explains. “It got out of control. And it creates a monoculture of one species that blocks out native plants that are more valuable in the landscape from an ecological perspective.” For example, honeysuckle berries aren’t nutritious. “It’s like fruit candy for the birds, whereas our native shrubs, like spicebush, produce berries that are high in oils—a better energy source for birds that are going to migrate back south in the winter.”

The honeysuckle also drives away pollinator insects that rely on native plants. “When the native plants—the spring wildflowers and the native shrubs—go, then those insects lose their hosts,” Dolan says. “It cascades down, and then the birds that would eat the insects don’t come to the area. And it continues on.”

After city leaders recognized the invasive nature of the honeysuckle, several organizations started removing the shrubs on a large scale in 2012. Dolan has been tracking the effort as part of her decades-long study of this species. Recently, she received a $7,500 grant from the Virginia B. Fairbanks Art & Nature Park: 100 Acres at Newfields to assess the progress of ecological restoration that began there in the early 2000s.

“Fairbanks Park is an amazing piece of property in the city,” says Jonathan Wright, the Ruth Lilly deputy director for horticulture and natural resources at Newfields. “We’ve been fighting invasive species for over a decade. We’re proud of the restoration efforts and how it’s progressing but we’re not scientists so we wanted to partner with Rebecca Dolan and quantify the quality of the work, and the quality of the habitat that’s returning.”

Dolan first started research at 100 Acres in 2002, when she was hired by Indy Greenways to inventory vegetation near what is now the Central Canal Towpath Greenway. In 2004, as the Indianapolis Museum of Art assumed control of the Art & Nature Park,  Dolan worked with Butler biological sciences professor Travis Ryan, herbarium assistant Marcia Moore, and biological sciences professor Carmen Salsbury to conduct additional vegetation and wildlife surveys in the area. Now, Dolan and Moore are going back to see what’s changed.

The researchers will tally and analyze the plant species along five transects—or linear sections of land—that were examined in the original study. Dolan will compare the findings with data gathered in 2004, assessing what has changed in the quality of the habitat as a result of restoration efforts. Dolan has yet to analyze data from Newfields—that report should be finished by the end of 2019. But she has been conducting similar research over the last five years in portions of Destination Fall Creek (DFC) along Midtown’s southern edge.

ADDITIONAL COVERAGE: DESTINATION FALL CREEK: Rejuvenating an Emerald Asset

The Mid-North Quality of Life Plan launched DFC in 2011 as part of a community-generated working plan. Leaders from adjacent neighborhoods enlisted Keep Indianapolis Beautiful (KIB) as a partner along with the collective impact group Reconnecting to Our Waterways (ROW) to collaborate on a long-term effort to remove honeysuckle and other invasive species.

Mark Adler, KIB’s vice president of special initiatives, helped coordinate projects for the Lilly Global Day of Service in 2012 when 2,000 Eli Lilly and Company employees swarmed around a three-mile section of DFC. They removed invasive trees and bushes, cleaned up trash, and opened up views of Fall Creek and its bridges and banks. Adler estimated that 760 cubic meters of chipped honeysuckle was removed in one day. “We were picking up piles of materials for days and days after the event,” he recalled recently.

Piles of honeysuckle await the chipper at the 2012 LIlly Global Day of Service. KIB photo.

The following year, Adler worked with community volunteers to plan a follow-up day of service that saw 2,700 Lilly employees and Ivy Tech students return to the Fall Creek corridor to continue invasive plant removal and replant the area with native trees, shrubs, grasses, and other perennials. These areas are included in Dolan’s research, which had documented honeysuckle density at 2,000 stems/acre—a very heavy infestation. According to her follow-up findings, the richness of the area’s plant life has more than doubled since 2012, mostly with native species. While overall habitat quality has shown some improvement, seeds brought in by wind and animals introduced eight new invasive plants. Early detection of these invasives will make controlling them easier, and she plans to continue monitoring the area.

Dolan says more urban communities are starting to understand how protecting local ecosystems can help defend against climate change effects. While Indianapolis doesn’t deal with more obvious problems like sea level rise, the city does have issues with flooding, erosion, and heat. Establishing more green spaces in urban areas can reduce these threats, Dolan says, but that will only work if the plants filling those spaces can get along with one another.

Katie Grieze is Butler University’s news content manager. A version of this story appears on the Butler website.

 Additional reporting by Thomas P. Healy.

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