To kill a weed: Chattahoochee Nature Center privet experiment yields results

Volunteers pull privet.

Thank you to Grants from Southern Company and Georgia Power for help supporting these efforts 

Do you know invasive, non-native plants like Chinese privet can be educational? Well, the removal of them can be. As part of a scientific experiment, the Chattahoochee Nature Center (CNC), in Roswell, Ga., is removing the privet that chokes our river boardwalk thanks to the help of scores of volunteers and a grant from Southern Company and Georgia Power.


“There is a great need to remove non-native plants,” said Henning von Schmeling, CNC’s horticulture director. “Our boardwalk is overrun with privet.”


Privet and invasive plants like it can squeeze out local species and take over. Much like kudzu, privet grows quickly and thickly, especially along water sources like the Chattahoochee River.


To help get rid of the privet, von Schmeling and CNC applied for and received a grant from the Five Star and Urban Waters Restoration program.


The need for healthy wetlands is important. Wetlands are among the most productive ecosystems in the world, comparable to rainforests and coral reefs in biodiversity. They play an integral role in the ecology of the watershed. In addition to providing habitat for reptiles, fish, waterfowl, mammals, and plants, wetlands absorb excess nutrients, sediment and other pollutants before they reach rivers, lakes, and other water bodies.


When rivers overflow, wetlands help to absorb and slow floodwaters, which can alleviate property damage and loss, and can even save lives. They are great spots for fishing, canoeing, hiking, and bird-watching, and they make wonderful outdoor classrooms for people of all ages.


So CNC turned the wetlands and its boardwalk into an experiment for all ages. Teams of volunteers work throughout the year clearing privet in predetermined areas. In each area, the privet is dealt with in a different way. One area is the “control.” That is, nothing is done.

Volunteers show off everything they pulled on a recent outing.

In the other four plots, differing techniques are used to clear the privet and help native biodiversity return. In some, the privet is pulled out by the roots and the exposed ground is either left alone or planted with new native species. In another, the privet is cut and an herbicide is painted onto the remaining stem to kill the roots.


The goal is to find out what works best, what is most practical and what is the cheapest to reproduce on a larger scale. Ripping out the privet works well, but is very labor intensive. The ground can then be planted with desirable native species (this works well), or left alone to allow plants in the “seed bank” to sprout.


Von Schmeling said a seed bank is where seeds can lay dormant in the ground for many years, waiting for the right conditions to grow.


“Seeds can last two, 10, 100 years in the ground if they are left undisturbed,” he said. “By removing the privet, we have allowed the seeds to germinate.”


Likewise, the plots using herbicide allowed these seed bank plants to grow as well, while killing off the privet. This allowed an increase in biodiversity.


“Biodiversity is very important to us,” said von Schmeling. “More biodiversity leads to a healthier environment and healthier animals.”


So far, von Schmeling said the results are showing the cheapest and easiest way to remove the privet is cutting the bush down and using herbicide on the stump (cut and paint). When this is coupled with augmentation using pre-grown plants, the biodiversity blossoms.


The work will continue; however, the project is nearing its end.


Von Schmeling said the work will continue on the site using the “cut and paint” method until all the privet is gone.


Funding for this grant was provided by the U.S. Environmental Protection Agency, Southern Company and Georgia Power, in partnership with the National Fish and Wildlife Foundation.