In an industry where high-tech solutions such as artificial intelligence and biometrics are constantly in the spotlight, sometimes the best path to efficiency and cost-savings is decidedly more low-tech. That’s the case for Appleton International Airport (ATW) when it comes to groundskeeping. The central Wisconsin airport is keeping things organic by using a flock of sheep to help tend its offsite wetlands.
With seemingly endless appetites, the sheep devour vegetation and eliminate invasive species such as buckthorn and Phragmites australis, more commonly known as ditch weed. And they usually work 24/7. The sheep are provided and managed by Wooly Green Grazers, an all-natural brush removal service located just six miles from the airport. What started as a test run last September worked so well that ATW contracted the flock for a full summer of work this year.
“Putting sheep to work for weed control might be a little outside the box, but it’s another example of how we seek continuous improvement and limit our carbon footprint,” said Airport Director Abe Weber after the 2023 trial.
 facts&figures
Project: Turf Management; Invasive Species Removal Sponsor: Appleton Int’l Airport, in WI Strategy: Using sheep to maintain wetlands Location: 17-acre Casaloma Conservancy Groundskeeping Service: Wooly Green Grazers Work Crew: 20-40 sheep (more in summer, when vegetation is thickest) Grazing Frequency: 24/7, spring through fall Cost: About $1,500/month vs. $2,500/month for traditional grounds crew labor & herbicides Project Timeline: Concept tested in Sept. 2023; full growing-season contract in 2024 Key Benefits: Cost savings; organic solution to removing invasive species, grass & other unwanted vegetation without harming newly planted trees & shrubs |
Wetlands Mitigation and Money Savings
The wooly animals are dispatched on Casaloma Conservancy, about 17 acres of natural wetlands ATW purchased in 2011 to balance airport land it had developed for runways and buildings. Located about five miles northeast of the airfield, the conservancy features natural viewing areas and nearly two miles of public hiking trails near the Wisconsin Timber Rattlers minor league baseball park, another popular family spot.
Once a year, airport workers plant new trees and shrubs on the property, but the land also needs to be maintained throughout the growing season. Airport Operations Supervisor Luke Bettis reports that ATW previously spent about $2,500 per month from spring through autumn to have crews clear brush, remove invasive plants and eradicate weeds at the conservancy. The process involved chemical herbicides and equipment that burns fossil fuel. Putting sheep on the job saves the airport about $1,000 per month and it’s organic, emphasizes Bettis.
“We actually wanted to use goats because they eat all of those invasive species, but it was explained to us that they will also eat the young trees,” he relates.
Roxie Emunson, who owns and operates Wooly Green Grazers with her husband, says that goats also tend to be more mischievous and push through fencing used to maintain grazing boundaries.
Before putting their sheep to work, the Emunsons make sure the land does not contain milkweed, because it is toxic for sheep. The same is true for Japanese yew, an ornamental tree that looks like a pine but causes cardiac arrest in sheep. Sadly, they learned that the hard way
last year.
Solar-powered electric fencing is used to keep the sheep grazing in one area, but also to protect them from their adoring public and natural predators such as coyotes and foxes. After the sheep clear one area, the fencing is moved to another.
The Emunson flock grows to more than 70 during the summer and dwindles to about 40 sheep by the end of autumn. Most are Olde English Southdown, also known as Babydolls, but some are crossbreeds. The crew working at ATW’s conservancy land includes 20 to 40 ewes and lambs.
Mighty Munchers
Despite their diminutive size, sheep can gobble up huge amounts of unwanted vegetation on sizeable tracts of land. In fact, they can eat up to 3% of their bodyweight every day. Having four stomachs allows them to digest highly fibrous foods. The first three stomachs turn it into a soup-like consistency, and digestion begins in the fourth.
“I think they just get tired more than full,” says Emunson. “They will take a rest when it gets hot. But you can be out there at 2:00 or 3:00 in the morning, and they’re eating away.”
Emunson visits the flock daily, and an onsite camera allows her to monitor the sheep remotely at any other time. “When you’re on a worksite, you learn quickly that the public is very interested in what we’re doing,” she comments. “A check that should take 10 minutes gets pushed to 30 because people want to talk about what’s getting done.
“I love the whole educational piece!” she adds. “A lot of people don’t know the conservancy is managed by the airport. And explaining invasive species and Phragmites—we enjoy that.”
She and her husband, Daniel, started Wooly Green Grazers in 2020 after he retired from the Marines. The couple and seven sheep moved to Wisconsin from North Carolina in 2022.
In addition to providing sheep for Casaloma Conservancy, they also have a flock at Renard Island, about 30 miles north of Appleton. The Port of Green Bay, which manages the county-owned island, reached out to Wooly Green Grazers after seeing a local news report about its flock working for ATW, and the Emunsons then bid on the project. The county reportedly plans to turn the island into a public recreation area, but decades of thick growth will need to be removed first.
What’s Not to Love?
Bettis still occasionally sends maintenance crews to the airport’s conservancy land to remove greenery the sheep can’t get to or won’t eat. Also, if there is a stretch of heavy rain, as there was this spring, the sheep have to be removed or only work in dry areas, because wet ground is bad for their hooves. In general, however, he considers the natural groundskeepers a major win—and an amusing novelty.
In past years, the Chicago Department of Aviation has used a variety of animals including goats, llamas and alpacas to clear vegetation at O’Hare International, but the practice is otherwise rare within the airport industry.
Based on their resounding success, however, sheep will almost certainly be baaaaa’ck at ATW’s offsite wetlands next spring. What’s not to love about an environmentally friendly solution that saves money and fosters good public relations?
