Pawpaw (Asiminia triloba) could once be found growing all over the eastern half of the US, especially favoring the rich alluvial soils of river valleys from the Missouri to the Potomac. It’s a small tree, rarely exceeding 20 feet, and in the wild it forms dense colonies (the “pawpaw patch” of the old folk song). The burgundy flowers, with their less-than-flowery odor, are not the first choice of butterflies or bees; instead, they’re mainly pollinated by flies, gnats and beetles. But the leaves of the pawpaw are essential to one butterfly: the zebra swallowtail.
Pawpaw leaves are the sole food source for the larvae of the zebra swallowtail (Protographium marcellus), and adults are often seen nectaring near the trees. Females choose fresh young leaves upon which to lay their eggs. The developing larvae feed on these leaves but may drop off the tree if disturbed by an enemy; older caterpillars may even hide in the leaf litter at the base of the tree. They’ll pupate on the pawpaw leaves, well-camouflaged as a dead leaf.
At the SBG, our pawpaws (currently flowering!) were planted by Dr Bob Snetsinger with zebra swallowtails in mind. You’ll find them in the Backyard Bird Habitat.
