A couple of different species in the genus Asimina go by the name pawpaw, but the common pawpaw (Asimina triloba) is far and away the most commonly encountered species.
Whereas the common pawpaw is found throughout much of the eastern United States, all other members of the genus are restricted to Florida, Alabama and Georgia. Authorities differ on the number of species in the group, with some only recognizing two and others recognizing as many as 10.
While pawpaw trees are somewhat interesting looking (especially when contrasted with most other native trees), they offer little value in an ornamental context. Their primary claim to fame is their highly unusual fruit.
A Favorite Fruit
Pawpaw fruit defy easy description. Reaching up to 6 inches in length, they are the largest edible fruit that native to the United States. Although they start out green, they often bear browns, yellows or even purple tones upon ripening. Technically a type of berry, pawpaw fruits contain a number of hard, inedible seeds.
Most people describe their taste as being similar to that of a banana (they are, in fact, used frequently in place of bananas in desert recipes), while others liken their flavor to that of a mango. Some note hints of papaya or strawberry. Their texture is better characterized as extremely soft and custard-like.
Those who enjoy the taste often prize them greatly, as they are not easy to acquire via commercial means. Pawpaw fruits are not easy to store for extended periods of time and shipping them is equally problematic – they turn to mush in short order. Some small-scale farmers have begun growing them for local markets, but short of the development of a storable cultivar, they are unlikely to become commonplace in your local grocery store.
However, pawpaws are sometimes available in frozen or preserved form. Some manufacturers have even started creating pawpaw ice cream.
A Taste of the Tropics
Pawpaws look somewhat out of place in eastern forests. Instead of the small, thin, finely toothed leaves of maples (Acer spp.), elms (Ulmus spp.) and birches (Betula spp.), these bottomland-inhabiting trees have large, smooth-edged leaves that look like they belong in a tropical rainforest. Although they can grow to proper “tree-sized” proportions, most wild specimens are rarely more than scraggly denizens of the understory.
While their physical characteristics are partially a manifestation of their habitat adaptations (for example, their large leaves are an adaptation that enables them to collect as much light as possible in the dim forest understory), they are also a manifestation of their evolutionary relationships. Pawpaws are members of the family Annonaceae, which primarily contains trees with tropical distributions. Some of its closest relatives living in the same forests include the magnolias (Magnolia spp.) and tuliptrees (Liriodendron tulipifera).
Pawpaw flowers are very interesting-looking. They bear six petals arranged in two rows – one outside row and an offset inside row. Somewhere between maroon and brown in color, the medium-sized flowers may occur singly or in groups. They’d be relatively inconspicuous were it not for their size.
They are also relatively scent-free, which is good; what smell they do emit is not terribly pleasant. In fact, the primary insects that pollinate the flowers (several beetle species) are those attracted to the smell of decay. Because these are not very effective pollinators, pawpaws produce relatively few fruit relative to the number of flowers they bear.
Subpar Seed Dispersal
Fruit-set is not the only thing with which pawpaw trees struggle: They are also poor seed dispersers. While plenty of animals also find pawpaw fruits to be delicious — raccoons, coyotes, foxes and opossums eagerly consume the fruit – few of them ingest, and ultimately disperse, the seeds.
To help cope with this evolutionary challenge, pawpaws often reproduce by forming large spreading colonies in hospitable locations. Some scientists have suggested that the poor dispersal pattern of pawpaws is the result of the extinction of a former predator (most likely a big herbivore that could ingest the fruit whole). Once these creatures died off, humans became the primary means by which pawpaw seeds have traveled ever since.