Rare Plant Rediscovered in Maryland after 112 Years

Riverbank Goldenrod Found in Montgomery County

Riverbank goldenrod (Solidago rupestris)

After 112 years, riverbank goldenrod has been rediscovered in Maryland. Department of Natural Resources Wildlife and Heritage Service Ecologist Wes Knapp and a team of researchers discovered the rare flower in Montgomery County.

“We know that the riverbank goldenrod’s seeds can easily travel by way of wind gusts and water flows,” said Knapp, who led the effort. “When I looked at the proximity of the Virginia population, I predicted riverbank goldenrod would be somewhere in the Potomac Gorge in Maryland, but there was no guarantee we’d find it. Plants don’t always show up where you expect them.”

In September 2014, Knapp, along with colleagues from the National Park Service, Virginia Department of Conservation and Recreation, and the Maryland Native Plant Society began their initial search along Olmstead and Bear Islands in Maryland’s portion of Great Falls Park.

It wasn’t until their second outing in September 2015, that the team ─ Knapp, and experts from the National Park Service and Salisbury State University ─ finally discovered a patch of goldenrods near Carderock, just west of Bethesda. A sample of the flowering plant was confirmed to be goldenrod by Dr. John Semple at the Waterloo Herbarium.

Riverbank goldenrod is a perennial, fall-flowering plant found along river edges scoured by floods. It was last documented in Maryland in 1903, but a small population was known to occur across the Potomac River in Virginia. Globally, the species is believed to be secure but is very rare on the east coast.

This rediscovery is part of a larger project the department is working on with NatureServe to identify rare plant species that may occur in Maryland based on their proximity in other states.  The project has resulted in the rediscovery of eight species, including the Susquehanna doll’s-daisy and the thread-leaved water-crowfoot.