Pawpaw (Asimina triloba): The Tropics Came North Once and Left This Behind

Plant Highlight · Asimina triloba · Southeast

For about three weeks in September the woods of the eastern United States produce a custard. Almost nobody notices, because the fruit will not travel, will not keep, and will not announce ripeness by any means except smell.

11 min read · By Fiona von Grey · Aiken, South Carolina

The ripe pawpaw arrives on the air before you see a thing. You come along a creek bottom in the second week of September, and there is a sweetness that does not belong to any tree you can name, something between banana and overripe mango with a floral edge underneath. Then you look up into the understory and find the fruits hanging in twos and threes like short green hands.

Color will not help you judge ripeness; Kentucky State University, which holds the USDA national germplasm collection for the genus, says plainly that color change is not a reliable indicator. The fruit should give under a gentle squeeze the way a ripe peach does, and come away with the lightest tug. The other method is to shake the tree and step back quickly, and the KSU horticulturists cheerfully recommend this while noting that they did warn you.

IA tropical family, one temperate holdout

Asimina triloba belongs to Annonaceae, the custard-apple family, and is the only temperate member of a family that is otherwise entirely tropical. The cousins are cherimoya, soursop and custard apple, all in the genus Annona, which is a family relationship rather than a close one, but the family resemblance in the fruit is unmistakable the first time you eat one.

The range runs from northern Florida to southern Ontario and west to eastern Nebraska, across roughly two dozen states. Habitat is the deep, rich, fertile soil of river bottoms, where pawpaws grow as an understory tree or a shrubby thicket beneath a taller canopy. That understory habit is worth holding onto, because it explains most of what the plant asks of a gardener.

Clemson calls Asimina triloba the largest edible tree fruit native to the United States, and that is the wording to keep. Fruits run one to six inches long and from seven ounces to as much as two pounds, occasionally hanging in clusters of three pounds. There is no other native fruit in this hemisphere's temperate woods with that kind of heft.

IIA flower built against self-pollination

In April the pawpaw flowers before the leaves are fully out, and the flowers are the strangest thing about the tree. Six petals, an inch or so across, in a dark maroon that reads almost brown, hanging downward on a short stalk with the fleshy texture of something that belongs in a rainforest. Clemson describes the scent as weak and unpleasant, which is fair; the tree is not producing a perfume, and the pollinators sought are flies and beetles rather than bees.

The mechanism underneath is more interesting than the smell. Pawpaw flowers are protogynous: the stigma ripens and becomes receptive well before the same flower's pollen is shed, and by the time the anthers open the stigma has gone by. Work published in the American Journal of Botany in 2017 put roughly eleven days between the two, an unusually long female phase. The flower is built, quite deliberately, against self-pollination.

Two pawpaws are not enough. Two different pawpaws are.

This is the single most important thing to know before buying, and it is where most disappointed gardeners go wrong. Pawpaws are self-incompatible, so fruit set requires pollen from a genetically different plant. Two grafted trees of the same cultivar are the same plant twice over and will not pollinate each other. Plant two different named cultivars, or two seedlings, or one of each. One cultivar, 'Sunflower', has been reported as self-compatible, but KSU is careful to add that this has never been verified scientifically, and we would not bet a decade of waiting on it.

IIIThe butterfly that has no alternative

If you plant nothing else on this page, plant a pawpaw for the zebra swallowtail. Protographium marcellus, still widely written Eurytides marcellus in the older literature, lays eggs on Asimina and on nothing else. Through most of the butterfly's range, common pawpaw is the only host available; in the Deep South a handful of other Asimina species are used, all of them pawpaws.

No pawpaw, no zebra swallowtail. That is the whole relationship, and there is no substitute plant to fall back on.

The caterpillars sequester annonaceous acetogenins from the leaves they eat, and those compounds persist in the tissues and wings of the adult butterfly, which is presumably the point of eating something faintly toxic on purpose. The larvae are also, and this is documented rather than folklore, highly cannibalistic, which is why females spread their eggs across young leaves rather than laying in clusters.

IVSeptember 1806, and the question of who moved the trees

On 18 September 1806, coming down the lower Missouri and nearly home, William Clark wrote in his journal that the party was entirely out of provisions and subsisting on pawpaws. They divided what biscuit remained, about one per man, and reckoned that this and the fruit would carry them the hundred and fifty miles left to the settlements. Clark noted that the men were "perfectly contented" and told the captains they could live very well on pawpaws. They reached St. Louis five days later.

There is a coda that has never been resolved. Some of the men fell ill during those pawpaw days: John Potts and George Shannon first, then others with inflamed and swollen eyes. Clark blamed sunlight on the water. Later scholars proposed infectious conjunctivitis. A third theory holds that the men transferred pawpaw skin to their faces by hand and developed an allergic contact dermatitis, a proposal the Park Service notes is disputed. Three explanations, no verdict, two centuries on.

The older question is who put the pawpaws where they are. Indigenous peoples across the eastern woodlands ate the fruit, and seeds turn up in archaeological deposits from Arkansas to Kentucky. A 2021 genetic study found that pawpaw populations near pre-Columbian habitation sites shared rare alleles with wild populations an average of 723 kilometers away, compared with 607 kilometers between wild populations, which is a signature of human-assisted long-distance movement. But a 2025 study working at the northern range limit concluded that distribution is primarily driven by natural dispersal, by water and by animals, with some populations possibly originating in planting.

The honest summary is that people certainly ate pawpaws and almost certainly moved them, that the seeds float and the fruit is eaten by everything with a mouth, and that the balance between those two forces is a live scientific argument rather than a settled story.

VEating them, honestly

The flesh is custard, eaten with a spoon straight from the halved fruit. KSU describes the flavor as banana combined with some rotating cast of mango, pineapple, melon and berry, and then adds the line that no marketing department would have permitted: there is considerable variety among wild pawpaws, ranging from awful to sublime, and while most taste good and some are truly wonderful, a few are better for throwing than for eating. Folk names include poor man's banana, American custard apple, and, depending on which state is claiming the tree, the Kentucky, Indiana or Michigan banana.

Why has this fruit never reached a grocery store? Shelf life, entirely. A fully ripe pawpaw lasts a few days at room temperature and about a week refrigerated. Picked slightly before full ripeness and chilled, the fruit will hold about three weeks and can finish ripening on the counter afterward, which is the only window in which shipping is even conceivable. Clemson notes the crop has real potential for roadside stands, high-end kitchens and processing, and essentially none for conventional distribution.

VIGrowing them, and the one season we will argue against ourselves

We spend most of September telling people to plant, because in the Southeast fall is when roots run and summer is what kills. We have made that case at length. Pawpaw is our exception, and honesty is worth more than consistency.

Clemson allows fall or spring but states a preference for early spring while the tree is dormant. Kentucky State is firmer: transplanting should be done in spring as new growth commences or soon after, and offers the most useful mental model available, which is that pawpaw behaves like a magnolia. Fleshy, brittle roots with very few fine hairs, and a long taproot that resents every disturbance. Container-grown plants give you the most latitude, and if you are planting one this autumn, plant a container plant and expect to baby them. If you can wait until March, wait until March.

	Asimina triloba
Hardiness	USDA zones 5 to 8 per Clemson and KSU; some sources extend to 9b. Chilling requirement is the limit, not cold.
Size	15 to 30 ft tall and nearly as wide
Light	Shade for the first year or two, full sun thereafter for fruit
Soil	Deep, fertile, well drained, pH 5.5 to 7.0. Will not tolerate waterlogging.
Pollination	Self-incompatible. Two genetically distinct plants required.
First fruit	Grafted, about three years. Seedlings, five to eight.
Deer	Foliage and twigs not browsed. Fallen fruit is eaten, and bucks rub trunks in winter.

The shading requirement surprises people and is not optional. Germinating seedlings are extremely sensitive to full sunlight, which can kill them outright, and this is precisely why pawpaws are almost always found in nature as an understory tree. Shade for the first year, sometimes the second, with a tree shelter or a guard on anything under three feet. After that, open sun produces the yields; a heavily shaded mature tree will fruit barely at all.

On deer, the news is better than the usual hedged claim. Deer do not eat pawpaw leaves or twigs, full stop. They will take fruit off the ground, and male deer occasionally damage young trunks rubbing antlers in winter, so a trunk guard through the first few winters is worth the trouble. In a woodland garden being eaten to the ground by deer, this is one of the few small trees you can plant with confidence.

Seed, if you want to grow your own

Do not let pawpaw seed freeze or dry out. Three days of drying at room temperature can drop germination below twenty percent. Cold moist stratification runs somewhere between seventy and a hundred and twenty days depending on which source you follow. Germination is hypogeal, meaning the shoot emerges without cotyledons, so the first thing above ground looks like a small stem with no seed leaves at all. Grafting works well, in whip-and-tongue, cleft or bark inlay; T-budding, softwood and hardwood cuttings do not work at all.

A humid-climate caution

Bordered leaf spot, Phyllosticta asiminae, is a fungal disease of leaves and fruit that becomes severe in humid climates, and there are no fungicides labeled for use on pawpaws. Airflow, spacing and patience are the whole toolkit. Ambrosia beetles will also find trees that are already stressed, which is one more argument for getting the establishment right.

VIIWhich pawpaw, and the other Asiminas

Kentucky State University holds the USDA National Clonal Germplasm Repository for Asimina, roughly two thousand accessions from seventeen states on twelve acres, and most serious cultivar work traces back there or to Neal Peterson. Peterson began breeding in 1980 while working as an economist for the USDA, drew on the surviving remnants of five early twentieth-century collections, and after twenty years of evaluating more than fifteen hundred seedlings released six varieties named for rivers: 'Allegheny', 'Potomac', 'Rappahannock', 'Shenandoah', 'Susquehanna' and 'Wabash'. 'Susquehanna' carries the largest fruit, sometimes over a pound, with the fewest seeds by weight.

For South Carolina specifically, Clemson's recommended list is worth reading closely, and two entries stand out for our climate: 'Duckworth #1' and '#2' originated in Florida and are best adapted to the Coastal Plain, and 'Mango' came out of southern Georgia. Those are the selections bred closest to home, and in a state where chilling hours are the real constraint, provenance matters more than reputation.

Pawpaw belongs, in the end, to the same argument we keep making about persimmon and blueberry and every other fruit that fell out of commerce because the supply chain could not accommodate the harvest. Some plants are worth growing precisely because you cannot buy the fruit. We wrote about the same idea from a different direction in Edimentals and, for the other great neglected native fruit, in American Persimmon: A Healing Gift.

The pawpaws are ripening as this goes out. If you have a shaded creek bottom, or a corner of the yard that stays rich and moist and never quite dries, you have the site. Buy two, from different parents, and put them in the ground where you will walk past them in September.

References

1. Clemson Cooperative Extension HGIC 1360, Pawpaw (South Carolina cultivars, zones, chill hours, planting, shelf life).
2. Kentucky State University Cooperative Extension, Pawpaw Planting Guide (Jones, Peterson, Turner, Pomper & Layne).
3. Kentucky State University, Pawpaw FAQ and Contact Information.
4. Kentucky State University, Pawpaw Description and Nutritional Information.
5. Kentucky State University, Evaluation of Genetic Variation Among Native Pawpaw Patches (USDA McIntire-Stennis KYX-90-09-1).
6. NC State Extension Gardener Plant Toolbox: Asimina triloba; Asimina parviflora.
7. UF/IFAS Featured Creatures EENY-58, Zebra Swallowtail, Protographium marcellus (Hall & Butler, rev. 2024).
8. Losada, Herrera, Lora et al. (2017), Pollen-pistil interaction in pawpaw, American Journal of Botany.
9. Wyatt et al. (2021), Ecology and Evolution, on anthropogenic dispersal of pawpaw.
10. Potts et al. (2012), Annonacin in Asimina triloba fruit: implication for neurotoxicity, NeuroToxicology 33(1):53-58.
11. Discover Lewis & Clark, journal entry for 18 September 1806.
12. National Park Service, PawPaw Sickness on the Lewis and Clark Expedition.