The Seminary at Forest Glen is an historic property located just inside the Washington DC beltway in Montgomery County, Maryland. Ecotone was contracted by EYP, Inc. to perform invasive species eradication services as part of the unique redevelopment project, which involved the restoration of many of the existing historic building on the site, as well as preservation of historic bridges and pathways. The “Glen” is a very old hardwood forest located in a stream valley on the site that had been colonized by exotic invasive species including Norway maple (Acer platanoides), Japanese knotweed (Polygonum cuspidatum), English ivy (Hedera helix), and oriental bittersweet (Celastus orbiculatus).



Ecotone implemented the invasive species control in several phases due to the heavy infestation and to ensure the best possible outcome. Bittersweet and ivy vines were cut from each tree trunk to leave a two to three foot open space around each trunk. Cut vines were immediately treated with a systemic herbicide to kill the roots and prevent regrowth. Norway maple trees that had colonized the former lawn area adjacent to the Glen and the nearby wooded area were cut at ground level and immediately treated to kill the root system and minimize suckering. The Japanese knotweed was sprayed with Glysophate several times to effectively remove the small colony. The initial treatment occurred in early summer of 2007, with a return in late summer of the same year. The site was revisited again in summer of 2008 to ensure that the treatments were successful and treat any surviving invasives.



The targeted species were effectively controlled with the phased treatment approach. Ecotone will continue to monitor the site to ensure that no infestation areas are allowed to regenerate. The invasive species control, combined with the restoration of the historic stone pathways and bridges, has made the Glen an important asset to this truly unique and innovative redevelopment project.