fbpx Skip to main content

Help Preserve and Protect Rare, Threatened, and Endangered Plant Species

in the C&O Canal National Historical Park


A Biodiversity Treasure in Peril

The C&O Canal National Historical Park (NHP) is beloved by millions for its natural beauty, rich recreational opportunities, and accessibility for millions of visitors. What is less well known is that it is one of the most biologically diverse national parks in the nation. Since its creation in 1971, over 1,500 plant species have been identified in the Park, including over 200 rare, threatened, or endangered (RTE) plants, some of which are globally rare and unique. But that number appears to be dwindling. Between 2008 and 2021, just over 100 previously identified RTE species were found along the C&O Canal. The remaining plants are likely now locally extinct. Invasive non-native plants, regional urbanization, and surging visitation have all taken their toll on the fragile habitats that make such diversity possible. With the addition of unfolding climate change, the National Park Service (NPS) is facing complex challenges to conserve this national biodiversity treasure. Its ability to meet these challenges, however, is severely impacted by capacity constraints resulting from ongoing shortfalls in the NPS operating budget.


A Unique National Park

Scour habitat along the Potomac River

Scour habitat along the Potomac River. Image courtesy of NPS.

The C&O Canal NHP spans 184.5 miles, traversing four physiographic provinces. From the Appalachian Mountains, through the Blue Ridge Mountains and the rolling farmland of the Piedmont, to its terminus on the Atlantic Coastal Plain in Georgetown, the C&O Canal NHP contains a rich mosaic of different habitats that host 68 distinct plant communities, 12 of which are globally unique. These habitats are the result of a variety of geological formations, most notably the Potomac Gorge and the shale barrens of the Appalachian range. Frequent flooding along the Potomac causes tree canopy gaps, scouring, and silt and seed deposition along the length of the river. Many northern and southern plant species overlap in the Park, with isolated populations of western species surviving where prairie habitat persists along the Potomac. Such diversity extends to fauna, which depend upon these varied ecological niches to thrive.

Along the Potomac Gorge, the geology and hydrology of the river flowing over Great Falls has created a biodiversity “hotspot” comprised of the most diverse flora located within an urban area on the entire East Coast. Upriver, the shale barrens of Allegany and Washington Counties, constitute a globally rare natural community where RTE plant and animal species are adapted to its harsh conditions. The steep slopes, constantly weathering shale, and continual undercutting of the Potomac limits soil development leading to the evolution of rare, endemic species found nowhere else in the world.

Biodiversity Campaign to support Rare, Threatened, and Endangered Plants

The NPS is focused on facilitating the long-term conservation of RTE plant species throughout the C&O Canal NHP through a partnership with the Mt. Cuba Center, a nonprofit native plant garden in Delaware, with a strategy that includes comprehensive identification, monitoring, habitat protection, seed collection, plant propagation, and establishing new populations of RTE plants in unique habitat niches in the Park. To ensure success, however, the Park needs the help of our canal community to supplement available NPS funding.

Snow Trillium (Trillium nivale) is a woodland, perennial wildflower that typically flowers between mid-March to early April. These plants grow in areas where there many other plants cannot, such as in limestone-dense outcroppings or areas where the soil is more gravely and sandy. Global Rank: G4, State Rank: S1 (Critically Imperiled). Photo by NPS.

White Trout Lily (Erythronium albidum) is a great pollinator and nutrient pool for other plants. These plants bloom in early spring and soak up many important nutrients from the soil, such as nitrogen and phosphorus. In the summer, when the blooms have disappeared and the plants die back, they release these nutrients back in the soil, providing nearby growing plants with the proper nourishment to sustain the warmer season. Global Rank: G5, State Rank: S2 (Imperiled). Photo by NPS.

Harbinger of Spring (Erigenia bulbosa) is one of the earliest blooming wildflower in the eastern US. By mid-spring, all traces of the plant above ground vanish, giving it its name, Harbinger of Spring. Global Rank: G5, State Rank: S3 (Vulnerable). Photo by NPS.

A Conservation Partnership with the C&O Canal Trust

With planning underway for the much-needed rehabilitation of the Billy Goat Trail System near Great Falls, the NPS turned to the C&O Canal Trust in 2020 to request funding to support a youth botany fellowship program to survey RTE plants in and around the area. With over 100 RTE plant species, the Potomac Gorge, where the trails are located, is considered a top biodiversity “hotspot,” and is also the area of the Park most imperiled by exceptionally high visitor numbers. The purpose of the survey was to collect data from known rare plant populations and identify other threatened species to ensure that work on the trail system is sensitive to fragile habitats and endangered plants. The NPS will use this information to identify and relocate at-risk plants or collect seed for their propagation. These efforts will allow the Park to ensure the continued survival of the plant species while providing sought-after outdoor recreational opportunities. As the C&O Canal NHP’s official philanthropic partner, the Trust was able to provide a grant of $64,757 to support this important work.

Over the spring and summer of 2021, the botany fellow located and identified 176 new and existing occurrences of RTE plants in the Great Falls area, and 331 RTE species occurrences Park-wide. Unfortunately, 91 species that had been previously known to exist in the Park before 2008 were unable to be located again.

The C&O Canal Trust has raised nearly $200,000 for the C&O Canal Biodiversity Campaign, thanks to our generous donors. 

To date, natural resources staff have planted nearly 2,000 individual propagules from 13 species, with a survival rate of 90-95%.

We are committed to preserving and protecting our Park’s incredible natural resources, but we need your help. Together, we can make a difference and ensure these plants do not go extinct.



For more information, please contact the development team at [email protected].

Top image by Chris Rief