For Extension Master Gardeners, community power is key to controlling invasive species
Rapidan River Extension Master Gardeners provide hands-on education for removing invasive species through a Giving Day-funded project.
Anyone with invasive plants or insects in their garden knows how frustrating these pests can be. You might spend hours removing the plants or squashing the insects, just to find more the next day. Controlling invasives can sometimes feel like a losing battle.
Anne Marie Pfaff, a Rapidan River Extension Master Gardener with plenty of experience fighting invasives, has this advice: Don’t give up.
“At the end of the day things will be better because you did something, even if it’s a small better,” Pfaff said.
As part of the Rapidan River Master Gardener unit, Pfaff recently organized and led a workshop teaching members of her community how to control the highly invasive tree of heaven, a species of tree native to China that rapidly spreads in Virginia ecosystems, competing with native species and even cultivated crops.
The workshop, organized in partnership with Blue Ridge Prism, addressed how to identify tree of heaven, how to use pesticides safely, and how to use the “hack and squirt” method to kill the trees. Supplies and take-home materials for participants were funded by donations to the Extension Master Gardener program received during Virginia Tech Giving Day.
“The grant we received allowed us to provide materials to participants to take home, which we couldn’t otherwise do,” said Pfaff.
“By providing these funds to units through our microgrant program, donations received during Giving Day are making an impact in Virginia’s communities,” said Ed Olsen, consumer horticulture specialist and Extension Master Gardener director. “In 2024, we focused on funding projects and workshops related to invasive species.”
“A workshop like this does two things,” said Pfaff. “It introduces why controlling tree of heaven is important, addresses the techniques and skills you will use, and it gives you a chance to go out in the woods and practice or see the technique demonstrated.”
Participants in the workshop were able to practice pesticide application methods using water and receive feedback from experts, which will be helpful when removing tree of heaven on their own property or elsewhere.
“The goal is to put the information and the tools in the hands of the people who will go out and use it,” Pfaff said.
“Community projects focused on invasive species removal are important opportunities for the public to learn about the issues associated with invasive species,” said Harrison Miles, a Ph.D. student in the Department of Forestry and affiliate of the Invasive Species Collaborative. “Knowing how to properly remove tree of heaven is particularly tricky. It looks similar to several native species and mismanagement may result in more sprouts than you had originally.”
Community-based invasive projects like Pfaff’s also have another purpose: They connect individuals and community partners for the future.
“Tree of heaven is not going to be controlled because of this one event,” Pfaff said. “We’re building relationships and groups within the community so that over years and years, when we have something that needs to be done, we will know who to call. We all build on each other’s work.”
According to Miles, the prevalence of invasive species in Virginia is increasing.
“In their native ranges, these organisms live in coevolved communities that keep each other in balance,” he said. “When we bring organisms to new environments, they are released from the stresses of their natural enemies, and this gives them an advantage over our native species. The future stability of our environment depends on early detection of invasive species, which is only possible with a well-educated public.”
How do you stay positive when it comes to battling invasive species?
“You just have to do what you can do, even if it’s just weeding a 1-square-foot area,” Pfaff said. “You do 1 square foot one day, and maybe when you come back the next day, you can do another square foot. Soon you have the whole bed weeded.”
For Pfaff, the ultimate goal is habitat restoration.
“I take out what is not supposed to be there and add back what is supposed to be there,” she said. “I do a lot of experiments toward that goal. Some work and some fail. You just have to keep trying different things and not get discouraged.”
For example, Pfaff has been using the “hack and squirt” method to control tree of heaven on her property for a few years, though it appeared she had made little progress. This year, her invasive trees are finally dying.
To learn more about invasive tree of heaven, see "Invasive Plant Species: Ailanthus (Ailanthus altissima)," Virginia Cooperative Exension publication.
Across the commonwealth, Extension Master Gardeners run hundreds of similar public-education programs each year. Contact your local Master Gardeners through your Extension office or learn more about gardening in Virginia and the Virginia Extension Master Gardener program.
