Invasive Plants

July 25, 2020

By Joshua Harkness

 Garlic mustard (Alliaria petiolata) is one of the greatest threats to the biodiversity of Perry Hill. Introduced as a garden vegetable, garlic mustard has escaped cultivation and now runs wild throughout our eastern forests. It frequently establishes itself in impoverished ecological communities, such as disturbed roadsides and abandoned agricultural lands. Its ability to spread and displace native flora is enhanced by overbrowsing by deer, poor forestry practices and forest fragmentation. In addition, it is known to poison mycorrhizal fungi and native insects. We control garlic mustard by pulling the mature plants before the release their seeds, and moving them to a central location where they are piled up in direct sunlight; this kills the plants and deprives the seeds that do germinate of the conditions they need to survive and reproduce. We have had much success with this method and need not have to use harmful chemicals to achieve control of this invasive species. We still have a lot of work ahead of us to eliminate the seedbanks where this plant has been established the longest but are making considerable progress towards this goal.Pictured is an infestation of garlic mustard on the edge of our forest, and a stand of blue cohosh (Caulophyllum thalictroides) which we regularly remove garlic mustard from.