nearly every weekend, whether there is sunshine, rain, or even snow, handfuls of volunteers trek to one of the select nature-filled areas within the limits of washington, d.c. these volunteers don gloves, shears and garbage bags as they step off the designated paths of rock creek park and get to work removing one of the most invasive plant species in the united states: english ivy.

the green-leafed vine snakes across much of rock creek park, crowding out native plant species that would typically take root and preventing sunlight and water from reaching trees as it surrounds and climbs their trunks. 

rock creek conservancy has held volunteer events such as these for nearly a decade. for two-hour stretches, either conservancy staff or weed warriors — individuals trained by the conservancy to properly identify plant species — lead groups of volunteers in removing invasive plant species from the park grounds.

the volunteers make a noticeable change: at the end of these events, vast stretches of ground once hidden beneath a sea of green leaves are made visible once again. following the events, the national park service rounds up the bagged plants and disposes of them, leaving a cleaner and healthier environment behind.