The Pawpaw Tree
Pawpaw (Asimina triloba) is a curious American native tree. Its first impression is that of a tree belonging to the tropics, from its large leaves to its banana-scented fruits. Don’t be fooled, it really is hardy far into the north.
Pawpaw (a.k.a. custard apple, wild banana) is a deciduous small tree or large shrub, commonly growing fifteen to twenty feet tall. As a tree, it often has a short trunk and spreading branches that form a broad pyramidal or rounded form. It may sucker heavily to colonize fairly large areas. The medium to dark green leaves may be up to twelve inches long and six inches wide, and turn a soft yellow in fall. The nearly two inch pale green flowers appear in May, and turn brown then maroon or purple. The fruits are somewhat oblong or pear-shaped and can weigh up to a pound. They are yellow-green at first, gradually turning to dark brown as they ripen in fall after leaf drop. Pawpaw is not particularly “ornamental” per se, but it is useful in naturalized areas and cultivated for fruit production. Hardy in zones 5-8.
Pawpaw is native from New York to Florida, west to Nebraska and Texas. Its earliest mention during America’s period of European exploration was in the 1540s, during DeSoto’s expedition into the interior of the continent from the Gulf Coast. In the lower Mississippi valley, this species once formed vast thickets with trees approaching forty feet in height.
Pawpaw has no commercial timber value, its wood being light, weak and coarse grained. Instead it is prized solely for its exotic fruit. Before Europeans ever headed west, the natives in eastern North America had a fondness for the fruit which led them to plant it wherever they went. Its love of deep, rich, acidic soil allowed it to flourish along river bottoms as well as in coves and hollows of the mountains. Often it is found as an understory tree, but it thrives in full sun.
As promising as the fruit may be, little headway has been made in commercializing it over the past 500 years. This may be due in part to the fact that the normal pollinators seem to have little interest in this species. Instead, the bulk of the work is done by flies and beetles, and other less efficient critters. Making matters even more difficult is pawpaw’s tendency to sucker. When large colonies of a single clone predominate, little fruit production occurs due to its self-incompatibility. Additionally, fruit quality varies significantly among individuals within the species. Work is underway, however, and several fine cultivars are available through Internet and catalogue sources for home fruit production. For most consistent fruiting, the gardener may need to assist in pollination duties.
Large pawpaws have a reputation for being difficult to transplant. Look for young plants, either balled in burlap or container grown, between three and six feet tall. The best chance of securing high quality fruit is by planting two different cultivars, even though there is at least one that claims to be “self fertile.” Provide the best site possible and maintain consistent soil moisture.
Prune suckers as they appear in order to maintain an orderly orchard. Use a small paintbrush to assist with pollination, if you wish to increase fruit production. Keep trees well mulched to cool the soil and retain soil moisture.
A Few Cultivars to Try