Nothin’ but pawpaws in the pawpaw patch

by Talia Ogliore, Washington University in St. Louis
January 9, 2025

Pawpaw fruits — the largest native fruits in North America — have become popular among foragers and foodies alike, with their custard-like texture and a sweet flavor often described as a cross between a mango and a banana.

Pawpaws are the state fruit tree of Missouri, and they tend to grow in dense clumps. They can reproduce clonally, meaning pawpaws can spread through their roots, much like aspen trees. Once one adult pawpaw gets established, it is likely to spread underground and send up lots of stems nearby. This trick of producing copies of itself is what ends up making a pawpaw “patch,” as memorialized in American folk song.

The patch is a good place for pawpaws but nothing much else, according to new research from Washington University in St. Louis. Pawpaw trees tend to choke out woody bushes and flowering plants nearby, exerting a haphazard kind of pressure on would-be neighbors.

“Pawpaws are leafy agents of chaos,” said Anna Wassel, a graduate student in biology in Arts & Sciences at WashU and first author of a new study on pawpaws in the journal Ecosphere. “Basically, we discovered that pawpaws create a habitat where the rules of which species can win in competition and persist are more random than when pawpaws aren’t there.”

Wassel’s team — dubbed the Pawpaw Patrol — investigated the effect of pawpaw on herbaceous community composition at Tyson Research Center, WashU’s environmental field station, located near Eureka, Mo.

“Previous studies have focused on how dominant tree species affect the number of plant species in the forest understory at smaller spatial scales, leaving open the question of how and why they affect variation in species composition at larger spatial scales,” said Jonathan Myers, a professor of biology in Arts & Sciences and co-author of the new study. “This study is among the first to explore how the presence of a locally dominant tree affects spatial variation in understory plant composition through non-selective or selective processes of community assembly.”

Keep reading: https://source.washu.edu/2025/01/nothin-but-pawpaws-in-the-pawpaw-patch/

Read the Ecosphere paper: https://esajournals.onlinelibrary.wiley.com/doi/10.1002/ecs2.70115