Spring ephemerals spend just a few weeks above ground in the early spring before retiring back to the soil. Their sparse weeks of liveliness are well spent, however, hosting scores of voracious pollinator species like bees, butterflies and flies in a window of time that is otherwise food scarce.
Dr. Kristine Hopfensperger, professor and director of the Environmental Science Program at NKU, says the obstacle of impermanence may contribute to a lack of research on ephemeral plants.
“I’m learning through this work, they’re really hard to study, because they’re like, ‘We’re here! We’re not,’” said Hopfensperger.
To learn how spring ephemeral plants can be supported—and in turn support pollinator populations—Hopfensperger is researching how spring ephemerals can be planted and sustained in areas after the invasive species Amur Honeysuckle is cleared out.
Ephemeral plants are perennials, meaning they sprout every year. Hopfensperger explained that their presence provides pollinators with a dependable source of food before the rest of the forest has bloomed for the season.
“When we were thinking about how do we create the best habitat for pollinators to thrive, you need that fall and spring, where they don’t have food,” said Hopfensperger.
The project is in collaboration with the Cincinnati Nature Center and the Greenacres Foundation. Both organizations have allotted land around Cincinnati for the research to be done on, and the Greenacres Foundation also awarded a grant to fund the project.
Working with community organizations gives the research a strong opportunity to be put into effect, said Hopfensperger. Not only do the organizations have workers who can help with the labor, but they can use the best practices and recommendations gleaned from the research to continue enriching the landscape for years to come.
“We’re actually contributing to a field that hasn’t been studied a lot. And these nonprofit organizations are going to be able to use that in a practical way to increase biodiversity,” said Zoe Robles, a student involved in the research.
Hopfensperger is leading two studies: one focusing on determining which ecological conditions are most suitable for spring ephemerals after honeysuckle has been removed, and another on which species of ephemerals propagate most effectively.
The latter project arose from challenges posed by the first project. Hopfensperger said that limited supplies and high price tags on spring ephemerals parlayed with their specialized growing conditions may steer land managers away from planting them in lieu of generic seed mixes that are often dominated by summer wildflower species. She hopes that developing effective strategies for growing ephemerals will spur land managers to give them a shot.
“With the propagation study, we’re trying to figure out: can people grow them themselves, so they don’t have to buy them from other companies, and if they need to grow them themselves, we’re studying the different environments to see which will work best,” Hopfensperger explained.
The first study uses 90 plots divided into quadrants. Ephemeral species were planted using different planting treatments in each quadrant to compare the efficacy of each method. The study utilizes four treatments so that the plants are sown at different maturity stages, including ordinary seeds, seed plugs, bare roots, and the final quadrant is left unplanted as a controlled variable. The team also measures soil and light characteristics in the plots to see how those factors influence the populations.
The second study grows ephemeral species in various environments, such as outdoors in trays, in greenhouses or a mixture of both, Hopfensperger explained.
“And then we’re going to transplant once they grow. We’re going to plant them in the forest and we’re going to follow them for a couple years to see, do they actually survive and create a new population,” said Hopfensperger.
“It will save money if they can grow it themselves, then it will also save money to see what type of growing environment does well,” she said.
Hopfensperger said the recommendations they generate throughout the study will be disseminated through the organizations’ newsletters so that land managers and workers can stay up to date on how to maintain the plants.
Partnering with community organizations also provides valuable networking opportunities for students, Hopfensperger said. She said that the Cincinnati Nature Center invites interested students to shadow land managers to experience the work first-hand.
One student working on the project, senior environmental science major Zachary Shreves, said he got a job at Cincinnati Nature Center in their conservation department thanks to the connections he made from the project.
Doing the research on land that’s open to visitors creates a natural forum for the public to learn about the project, Shreves pointed out.
“Just working there, people would ask all the time, like ‘what are these plots, what do you guys do,’ and so at a place where it’s public, like the Nature Center, these projects are also a good way to kind of get information out to the public or help them learn something they might not know already just because they’re curious,” said Shreves.
With spring upon us, ephemerals are rearing, so Hopfensperger and her team are working on collecting this year’s data for comparison to previous years.
Data collection for the first study will conclude after the summer of 2025. It will end after the spring of 2026 for the second study.
“It’s not like we transplant these and walk away. You want to know what’s happening,” said Hopfensperger. “That’s kind of how restoration goes. You establish things, make sure they’re there and they’re going to stay there, and then you come back every few years.”