Rediscovery of the Unique Yadkin River Wildflower

by Crystal Cockman

August 26, 2015

There’s a special wildflower that grows only in two places in the entire world and both are in the Uwharries – below Badin Dam and below Tillery Dam. John Kunkelay Small of the NY Botanical Garden made a trip to the Piedmont in 1894 and first documented it. He found this old goldenrod, Solidago plumosa, or Yadkin River goldenrod, which he named in a paper in 1898. He included it in his Manual of the Southeastern Flora up to 1933. 

One of the most popular plant reference guides now, Radford, Ahles, & Bell’s Manual of the Vascular Flora of the Carolinas (1968), did not include it. However, Arthur Cronquist, an expert on the composite family (in which goldenrods are included), maintained that it was a good species. The former Curator of the NC Herbarium, Steve Leonard, kept in contact with Alan Weakley, with the NC Natural Heritage Program, about the species, saying “someone needs to go rediscover this plant”.

In 1994, Alan was doing fieldwork for the Carolina Vegetation Survey (http://cvs.bio.unc.edu/) and he and his team member,

Tom Philippi, did a plot in the Uwharries. They finished up early and had aerial photos from the US Forest Service from their work, so they noticed rock outcrops below the dams.  As you might suspect, this flower needs some specific conditions to grow. It is a “river scour plant”, which means that it grows out of crevices in exposed rocks on riverbanks that are exposed to scouring in flood events caused by heavy rain events.  This scouring maintains open, sunny conditions that these plants need.

Alan and Tom drove the 5 miles or so down the USFS gravel road to that area and found a goldenrod growing abundantly that they had never seen before in their lives, knowing that it had to be Solidago plumosa. They checked it with Cronquist’s manual and other sources, and realized they were correct. It was 100 years to the day since JK Small had seen the plant, and no one else had consciously seen it since.

Alan emailed Nora Murdock with the US Fish and Wildlife Service to let her know about his rediscovery, and he got a call back the next day that Steve Leonard had found the plant there as well – the day after Alan was there. So two botanists within 1 day of each rediscovered this plant that was lost for 100 years.

The plant originally occurred on a 5-10 mile stretch of the Yadkin River in the

Uwharries where a lot of scour action occurred, on mafic rock outcrops along the course of the river. The building of two dams in the 1920s removed the scour action. The only remaining plants are below dams and receive some scour from flood releases. They are found on this mafic rock because it has a high pH.

The scouring removes the parts of the plant that are exposed out of the rock, but they regenerate from rhizomes back in the rock crevices. There are other plants that live in those scouring environments but no other notable ones in North Carolina. Keep an eye out for this unique wildflower in bloom if you’re paddling at the Narrows in late September or early October.

Special thanks to Alan Weakley for the information provided in this article.