The rarest wildflower in all of New England, sandplain gerardia, is found in just a handful of places in the world, including in a historic cemetery in Richmond. How it got there and why it has survived when it disappeared almost everywhere else is anyone’s guess – though there are plenty of theories. But biologists throughout the region are working to ensure that it can continue to thrive in the Ocean State.
The small, pink-flowering plant, a member of the pea family and found exclusively in southern New England and Long Island, is easy to overlook. “It’s such a tiny plant that if you’re not looking for it, you’d have to trip and fall on your face to see it,” said Scott Ruhren, senior conservation director for the Audubon Society of Rhode Island. “It barely pokes its head above the grass.”
Like the Rhode Island population of the plant, most of the sites where sandplain gerardia naturally occurs are historic cemeteries, which causes many people to wonder why it only seems to thrive in this particular environment. Some scientists have suggested that it’s because the plant grows best in sandy, poor quality soil, and many historic cemeteries have sandy soils because the soil conditions weren’t conducive for growing crops by early colonizers. Others think it has to do with the relationship between the rare plant and the other plants that happen to grow in historic cemeteries, like little blue stem grasses. Sandplain gerardia is a hemi-parasite, which means its roots latch onto the roots of these adjacent plants to acquire additional nutrients.
But Ruhren thinks the success of sandplain gerardia in historic cemeteries has more to do with lawn mowing. He said that historic cemeteries tend to be neglected more than big cemeteries that are often intensively mowed. The less intense mowing regime may benefit the plant by stimulating it early in the season when mowing typically occurs more frequently and allowing it to grow and bloom later in the summer without mowing,
That’s why the Richmond cemetery site is mowed just once in the fall and spring and then roped off so the 200 square-foot area where the plants grow isn’t mowed during the summer months. Charles Brown, a wildlife biologist for the Rhode Island Department of Environmental Management, has done the roping and mowing the past two years, and he said he counted just 15 plants in the entire population last year. While plant numbers fluctuate widely from year to year, most years the site hosts fewer than 100 sandplain gerardia plants.
“Mowing also helps disperse its seeds,” said Ruhren. “It’s an annual, so what happens this year influences next year’s success. By mowing, you help to spread the seeds. For a rare plant, it can take some mowing abuse, but it’s also wimpy when it comes to competitors. If shrubs and vines move in, that will be the end of the species.”
With that worry in mind – and due to the precarious nature of the Richmond cemetery population – retired DEM biologist Chris Raithel worked with partner organizations to cultivate additional sites elsewhere just in case the cemetery plants don’t survive. Using seeds collected from the local plants as well as those stored in a seed bank maintained by the Native Plant Trust in Massachusetts, new populations of sandplain gerardia were established at Trustom Pond National Wildlife Refuge, the Audubon Society’s Eppley Wildlife Refuge, and at a site maintained by the Richmond Conservation Commission. (Exact locations are a close-kept secret to avoid disturbance by plant collectors and vandals.)
The Audubon site, established in 2003, has flourished and now fluctuates between hundreds and thousands of plants each year. The Conservation Commission site was planted in 2013 and last year had nearly 200 plants, according to Commission chairman Jim Turek.
“We selected a grassland habitat where broom grass is the dominant species and is needed by sandplain gerardia to proliferate,” said Turek. “The Commission maintains the site by mowing the circular area each fall and removing excess thatch. And the project has worked well.”
The Trustom Pond site thrived and sprouted more than 1,000 plants shortly after being planted in 2011, but it soon declined to fewer than 20 and none have been observed since 2018.
The plants may face a new issue in the coming years. Recent research by biologists with the federal government, which has listed sandplain gerardia as an endangered species since 1988, has concluded that the species may not be a full species after all. It may, in fact, be a subspecies of ten-lobed foxglove, a similar-looking plant that ranges from Massachusetts to Alabama and is not on the federal endangered species list. A new assessment of the two species is underway to determine if, when combined as one species, it deserves federal protection. That assessment is due to be completed next year.
Depending on how the assessment turns out, local agencies may not devote as much effort to monitoring and managing the area’s rarest wild plant, though all those involved hope it will continue to thrive and even expand its range and number in the area.
“It’s historically been found along roadsides, so there may be more out there somewhere,” said Ruhren. “It’s inconspicuous, so I wouldn’t be surprised if it turns up someplace that the conservation community didn’t know about, somewhere that has been overlooked.”
Maybe even in another of Rhode Island’s 2,800 historic cemeteries.