Pawpaw (Asimina triloba) of the Custard Apple (Annonaceae) family is a small deciduous understory tree with edible fruit. It is widespread in the deciduous forests of the eastern U.S., from eastern Texas and southeastern Nebraska, east across southern Michigan to the Atlantic Coast from Pennsylvania to northern Florida. In Arkansas it occurs statewide. The genus name is based on the Native American name “assimin.” The specific epithet refers to the number of petals and sepals. The common name “pawpaw” was first used by the English in the 16th century for papaya (Carica papaya) and later used by early American settlers for this species. Along with various spellings of pawpaw, other common names include Arkansas banana, wild banana, custard apple, and banango. Habitats include deep, mesic, sandy to clayey soils of rich, shaded bottomlands, floodplains, ravines, and slopes. Pawpaws have deep taproots with shallow runners that produce nearby clonal sprouts. Trees have slender and branch-free lower trunks. Mature trees are typically from 15 to 20 feet tall, but may reach 40 feet.
Leaves and branches are alternate, in two opposing rows, however this arrangement becomes less noticeable as some branches and twigs become dominant while others die away. Short reddish pubescence on new branches is lost as they age and become glabrous. New bark is yellowish green before becoming reddish brown to gray during the first year. Bark of mature trunks is thin, gray to gray-brown, with lighter splotches, corky lenticels (air pores), and minimal fissuring.
In late March into mid-April, single flowers emerge from rounded lateral buds along year-old branches. In mid-winter, the dark fuzzy flower buds are knobby. With anthesis approaching, they become yellowish green before changing to deep reddish brown to purple. First flowers tend to open before leaves appear, but then leaf growth and flower progression continues simultaneously for about a month.
Flowers, about 1½ inches across, are pendulous, with three sepals, and a veiny corolla of three larger outer petals and three smaller inner petals, both whorls a striking maroon to reddish brown. Pedicels and sepals are covered by a dense reddish brown pubescence. Flowers have a somewhat fetid scent which attracts pollinating flies.
Flowers have an elongate receptacle bearing a dense mass of numerous stamens surrounding a cluster of 3-6 separate pistils. The stamens have stubby filaments topped with tightly packed, pale yellow anthers that en mass create a brain-like surface. Pistils consist of elongate ovaries, with short styles and rounded yellowish stigmas. After anthesis, stamens disintegrate as the receptacle shrinks to eventually form a “ring-collar” at the base of the fruit.
Leaves emerge after flowers have begun to bloom. Short, reddish pubescence is lost with leaf maturity. Simple oblanceolate leaves grow to about 1 foot long and 3½ inches wide with ⅜-inch petioles. Margins are entire. Crushed leaves have a strong, distinctive scent, like green peppers––a useful field character.
Pollinated flowers may produce one or a cluster of several rounded to oblong fruits (large berries) 1-4 inches long. Fruits develop from bluish green to yellowish as they ripen and may weigh a half-pound or more. An isolated tree may produce fruit, but cross-pollination increases fruit production. The greenish pulp becomes white to yellow, soft, sweet, and delicious as the fruit matures. Fruits contain to about 10 dark brown, inch-long, smooth and shiny seeds in two rows. Peduncles, at fruit maturity, may be an inch or more long.
Pawpaws, with their large leaves, striking flowers, and delicious fruits, merit a special place in gardens and natural areas. They are easy to grow in partially sunny areas as well as, once established and with adequate moisture, sunny areas. Trees in sunnier areas will be less leggy and bear more flowers and fruit. The fruits have a banana-mango (?) flavor appreciated by many people. If a colony is not desired, clonal sprouts need to be removed annually. In early winter, those sprouts can be successfully transplanted with appropriate care (shading and watering). Leaves are not eaten by deer, but fruits are a favorite of deer, box turtles, raccoons, and other small mammals. Pawpaws are host plants for the Zebra Swallowtail (Protographium marcellus), Pawpaw Sphinx Moth (Dolba hyloeus), and the Asimina Webworm Moth* (Omphalocera munroei).
Dwarf pawpaw (Asimina parviflora), a species of conservation concern in Arkansas, is the only other species of the genus in Arkansas (Miller and Union Counties). Dwarf pawpaws are more shrub-like with significantly smaller but similar leaves, flowers, and fruit.
* Caterpillars of Asimina Webworm Moth bind terminal leaves into ugly wads of dead leaves. As long as the terminal buds are not damaged, branches continue normal growth the next spring.
Article and photographs by ANPS member Sid Vogelpohl