By Ben Sapperstein, Quinlan Campbell, and Leighton Reid
Ben Sapperstein and Quinlan Campbell are undergraduate researchers in Leighton Reid’s Restoration Ecology Lab at Virginia Tech.
Peter’s Mountain Mallow (Iliamna corei) is among the rarest plants in the world. As of 2025, only five individuals remain in the wild, all of them clustered in a single population on a rocky ridge in southwestern Virginia. In the 98 years since its discovery, Peter’s Mountain Mallow has teetered on the edge of extinction and come roaring back like a phoenix from the ashes, but today its future is again uncertain.
First discovered in 1927 by two botanists from West Virginia, Peter’s Mountain Mallow is a showy wildflower with light pink, hibiscus-like flowers. In full sun it reaches an impressive 2-m stature, with multiple stems covered in fuzzy, maple-like leaves. The blossoms are slightly smaller than the aperture of a coffee mug. They feature prominent columns of fused stamens tipped with yellow pollen. Uniquely, the flowers have no discernable scent.
The mallow’s habitat is a unique pine-oak woodland situated on a rocky ridge above the New River. The ridgetop is underlain by calcareous sandstone, which lends a richer feeling to this site than nearby ridges, which are much more acidic. For example, the plant community includes calciphiles like white-flowered leafcup (Polymnia canadensis), toothache tree (Zanthoxylum americanum), and American barberry (Berberis canadensis). Other species include honey locust (Gleditsia triacanthos) and northern leatherflower (Clematis viorna) – a distinctly rich ridgetop assemblage. Historically, the site had an open canopy that also supported sun-loving plants like Monarda and Coreopsis, but the canopy has apparently closed in and these are no longer evident.
Fire required
Today, Peters Mountain is densely forested, but this may not always have been the case. Pine trees there bear fire scars showing that the mountain burned many times in the past. From the late 18th Century until the 1940s, Peters Mountain burned on average every second or third year, but after the 1940s fires abruptly disappear from the record. This reflects a change in federal policy towards fire suppression that affected forests throughout the United States.
The loss of fire coincided with a decline in the mallow population. In 1927, when Perry Strausbaugh and Earl Core discovered it, they estimated that there were no more than 50 plants. Botanists in 1962 found the population little changed, but by 1985 the population was decimated – with only five individuals remaining.
The US Fish and Wildlife Service added the mallow to the Endangered Species List in 1986, and a recovery plan was written by 1990. Yet in 1993 the population hit rock bottom with just three plants. Researchers at Virginia Tech and elsewhere mounted investigations to understand the cause of the mallow’s decline and clues about how best to assist its recovery.
A germination experiment in the early 1990s revealed a strong connection between fire and Peters Mountain Mallow. Jerry and Carol Baskin at the University of Kentucky tried to germinate a batch of mallow seeds, but only a tiny proportion (3%) grew. When they burned the seeds, the germination rate increased 13-fold, to 39%. The Baskins further increased seed germination by repeatedly heating the burned seeds to 80-90°C, ultimately achieving a maximum germination rate of 71% – nearly 24 times the baseline rate. They concluded that Peters Mountain Mallow forms a persistent seed bank and requires fire to break seed dormancy and trigger germination.
Population restoration
These two lines of evidence – germination studies and fire history – suggested that a prescribed fire campaign would help reinvigorate the mallow population. A consortium of institutions rose to the challenge, including The Nature Conservancy and the Virginia Department of Conservation and Recreation. Burning the site was not easy. Fire crews hand-carried heavy tools, water, and drip torches off-trail up the side of the mountain. They created fire lines through steep, intact forest to prevent fire from spreading into the adjacent Jefferson National Forest.
Initially, the ridgeline habitat was burned twice, once in 1992 and again in 1993. The return of fire led to a dramatic population increase as hundreds of seeds in the soil seed bank broke dormancy and germinated.
In addition, the few remaining adult plants were caged to prevent wandering deer and other herbivores from eating them. Land managers removed trees, shrubs, and herbs with hand tools and herbicide to increase light availability. Two particular targets were white-flowered leafcup and garlic mustard (Alliaria petiolata) – an invasive species.
As a further precaution, experimental populations were created offsite, including two at Virginia Tech. Some of the seeds from these garden plants were preserved frozen at the North Carolina Botanical Garden. Others were broadcast back into the habitat to await the next fire – and their opportunity to recruit into the population.
In June 2004, lightning struck and a hot wildfire consumed the mountaintop. This conflagration followed two exceptionally dry years in which the Peters Mountain Mallow population failed to produce any fruits. The wildfire again stimulated germination of seeds in the soil seed bank, and a flush of mallows appeared over the next two years.
Further burns in 2008, 2009, 2010, and 2011 assisted in growing the population from 74 individuals in 2005-2007 to an average of 110 individuals each year from 2012-2014. In May 2017, a multi-agency team burned the Peters Mountain Mallow habitat one last time. The vegetation was green, and the fire was smoky, but the population that year was robust. The team counted stems (an individual plant can have several) and found 345, down from 630 the year before. This was the last fire ignited on Peters Mountain before the COVID-19 outbreak. There has not been another one since.
Reinvigorating research
On a steamy morning in July 2024, a small group of ecologists, botanists, and land managers climbed the mountain to see how Peters Mountain Mallow was faring. One of us (Leighton) accompanied others from the Massey Herbarium, The Nature Conservancy, and the US Fish and Wildlife Service. What we found was disappointing. The mallow flowers we hoped to see were shriveled and dry from a prolonged drought. Worse, there were only a few of them. We did not do a thorough census, but this trip sparked the notion that the mallow required renewed attention.
For many years, researchers at Virginia Tech were heavily invested in this species – measuring the population, collecting seed, growing plants, performing genetic and physiological studies – even carrying jerry cans up the mountain to water plants during droughts. But this involvement waned as faculty retired and students moved on to other things. It seemed like a good time for a new wave of researchers to join the effort. Moreover, students in the newly-formed Ecological Restoration major had created a Society for Ecological Restoration student association (SER-VT) and were seeking a local project.
Our first action was to formally survey the population. Last July, we laid out a transect to measure and map every individual. It did not take long. Since the last population inventory in 2018, the world’s only population of Peters Mountain Mallow has declined from 155 stems to just ten, representing only five individual plants. This is the same number of plants that there were when the species was first listed on the Endangered Species Act in 1986.
What’s more, only two of the plants were large enough to produce flowers this year, and the flowering times were misaligned so that one plant was setting flower as the other was senescing. Peters Mountain Mallow requires cross-pollination, so no seeds were produced last year.
While disappointing, this information is valuable for understanding the species’ boom-and-bust population dynamics and informing land managers about the acute need to bring fire back onto this landscape in the near future.
Looking backwards to move ahead
We know from the pine tree study that Peters Mountain burned frequently over the past two hundred years, but presumably the mallow has lived here for much longer. In what sort of environment did it evolve? Another undergraduate researcher, Nisha Polk, is using a different approach to construct an older, precolonial environmental history – and a potential reference for land managers to emulate.
In October, Nisha climbed the mountain with Dr. Rachel Reid, a conservation paleoecologist in the Virginia Tech Geosciences Department. Nisha and Rachel inserted PVC tubes into the ground to collect soil cores from small pockets of earth between the boulders that make up the ridgetop. The soil is thin, no more than 25 cm, but it could contain organic matter from as much as 2,000 years ago.
Over the next few months, Nisha will analyze the carbon isotopes from the soil organic matter to learn how old the soil is and what kinds of plants produced it. To age the soil, they will use carbon dating, which estimates when the soil was formed based on how much of the radioactive carbon-14 isotope is present. Then they will study the ratio of stable carbon-13 and carbon-12 isotopes to learn about past vegetation. In essence, lower ratios indicate plants that use a C3 photosynthetic pathway, including most broad-leaved plants that make up the temperate forests in our region, while higher ratios indicate plants that use a C4 photosynthetic pathway, such as warm-season grasses adapted to open grassland, savanna, and open woodland habitats. In other words, carbon isotopes can tell us what the predominant ecosystem was here over hundreds or thousands of years.
A bright future?
While Peters Mountain Mallow is again in the single digits worldwide, there are reasons for hope. First, the species produces a robust seed bank that may revitalize it when the site is next burned (hopefully soon). Second, the North Carolina Botanical Garden maintains a collection of its seeds – a back-up if the worst should happen. Third, the habitat is owned by The Nature Conservancy, whose land managers are committed to ensuring the species’ persistence. Fourth, the species is protected by the US Endangered Species Act, a 1973 law that is estimated to have prevented the extinction of more than 70 species.
Finally, Virginians should have hope for the future of this botanical crown jewel because a new generation of undergraduate researchers is engaged, bringing fresh energy and insights to the cause, documenting the species’ ups and downs, and uncovering its natural history. Over the next five years, we envision an undergraduate-led research agenda that includes monitoring the mallow population, using paleoecology methods to learn about the long-term environmental history of the species’ habitat, and refining our understanding of its ecological niche.
