Pawpaw (Asimina Triloba)
Pawpaws (Asimina triloba) are the largest fruit native to North America. Their ruggedness and versatility make them ideally suited to the backyard orchard or small-scale market grower. The fruit, which resembles a mango in shape, has a sweetness more often associated with produce native to the southern hemisphere.
The pawpaw is the only temperate climate member of the Annonaceae family of tropical fruits that include cherimoya, sour sop and custard apple
Pawpaws are found in the wild from New York west to Nebraska, and south to Florida and Texas. In regard to hardiness, established trees can withstand true zone 5 winters of -20° F. Young seedlings and grafted trees should be protected during their first few winters.
In addition to zone hardiness, another equally important factor in determining whether a crop is suitable for planting in a given area are its growing degree day (GGD) requirements. GGD measures heat accumulation over the season and helps to predict when a given crop will ripen. GDD are calculated by taking the average of the daily maximum and minimum temperatures compared to a base temperature of 50 degrees F.
Pawpaws require a minimum of 2,200 GGD which means that pawpaws have adequate summer heat to ripen in all but the coldest areas of Connecticut such as Norfolk in Litchfield county. With climate change, pawpaws may become viable in the entire state. To determine the GGD in your area, use this calculator from Oregon State University.
Insects and deer show a natural aversion to pawpaws, a result of the fatty compounds called acetogenins that are produced by the trees. The compounds are found in the leaves and twigs, and are what give crushed pawpaw leaves and bark their very strong and distinct peppery smell. According to some recent research, extracts of acetogenins may have useful applications as a natural pesticide.
Another intriguing use of pawpaws are their potential use in fighting cancer. In vitro studies at Purdue University have shown that pawpaw extracts, and more precisely the acetogenins, are effective against certain lines of cancer cells. These preliminary results have led some to rapturously describe pawpaws as an anti-cancer super food. While this may eventually prove to be the case, more studies are required. Extensive clinical trials have yet to be conducted with pawpaw extracts.
As any Connecticut gardener knows, our deer have voracious appetites and eclectic palates. Despite the acrid taste of pawpaw leaves, I have on occasion had deer browse young trees. This, combined with the risk of deer trampling small trees, has taught me to protect vulnerable young pawpaws with chicken wire cages for the first few years.
Like many fruit trees, pawpaws take some time to reach fruit-bearing age, generally about 6 to 8 years old. Even before they begin to produce fruit, pawpaws provide interest in the landscape with their long, slender, teardrop-shaped leaves.
In the wild, pawpaws are found in greatest abundance as understory trees in humus- rich soil, often along river and stream banks. From this comes the notion that pawpaws will grow in the shade. While this is true, growth is leggy and fruit production limited. For best results under cultivation, site a pawpaw in full sun, in an area with rich soil with a pH between 5 to 7.
Most sources state that two genetically distinct trees are necessary for cross-pollination, though there are some trees that are self-fertile. In order to ensure pollination and fruit set, plant two different grafted cultivars or seedling pawpaws, no more than 20 feet apart.
Pawpaws flower in mid-May, and somewhat resemble downturned purple trillium blossoms. The petals are a beautiful shade of dark brownish purple. The unusual look of the flowers attracts an interesting gang of pollinators. Beetles and blow flies, insects associated with carrion, which the scent of pawpaw flowers mimic, are the principal ones. Don’t be put off with a vision of swarms of flies attracted to the fetid odor of flowering pawpaws. The scent is very slight and not at all disagreeable, or even discernible.
The fruit is mango-shaped and greenish-brown when ripe. Individual fruits can weigh between 4 ounces and 1 pound, and the flesh is soft and juicy. The skin always retains a slight astringency even when ripe, so this must be avoided along with the large kidney shaped seeds.
Wild fruit tend to have a high seed to flesh ratio. One goal of recent pawpaw breeding programs is to develop cultivars with fewer and smaller seeds.
In my experience, the flavor varies greatly between different trees, with some rather bland, and others cloying. But the best taste like banana custard with notes of pineapple and mango.
Opinions regarding the flavor of pawpaws have changed greatly over the years. Prior to the European invasion, Native Americans in the south and mid-Atlantic region cultivated pawpaws for their fruit. The name of the pawpaw’s genus, Asimina, is derived from the Algonquin name for the tree. Native American cultivation of pawpaw is responsible for the trees ‘native’ range today. Stands of ‘wild’ trees along the northernmost tier of the pawpaw’s range, ringing areas of Lake Ontario are the remnants of Native American orchards.
In the period of exploration and conquest by European settlers, pawpaws ranked highly among the newly discovered fruits of the New World. A Portuguese officer in the company of the conquistador Hernando de Soto described the fruit as having a “very good smell, and an excellent taste.” In 1806, during a lean period of the return leg of their westward exploration, the expedition lead by Lewis and Clack subsisted on pawpaws. The high regard for pawpaws in elite circles was such that Thomas Jefferson sent seeds to his horticultural correspondents in Europe.
Despite this early prominence and praise, the late 19th century the horticultural attitude towards pawpaws remained unsettled. A typical assessment was given in an 1885 issue of Vick’s Monthly Magazine, which described a “pulpy mass, of a flavor which is not at first relished, but for which a taste can be acquired.” Charles Sprague Sargent, a giant of American botany and horticultural sang the tree’s praise as both and ornamental and edible in his monumental work Silva of North America. Sargent argued that pawpaws are “well worth a place” in ornamental gardens for their “large and conspicuous foliage” and “handsome flowers and fruit” As to eating quality Sargent was unequivocal, rating pawpaws “sweet and luscious to the taste.”
Into the early 20th century, minority of horticultural writers were as dismissive of pawpaws as others were enthralled. A popular work on the trees of North America published in 1905, The Tree Book by Julia E. Rogers, dismissed the flavor of the fruit as "insipid." The author goes on to state that pawpaws are "delighted in by the Negro of the South. It is sold in markets, but is too sweet and soft to be really enjoyed by more fastidious people."
The stark racism of this statement is jarring when read today, but may reflect a reality of the time. Some members of a prim Victorian establishment who favored more traditional fruits were biased against pawpaws and those that ate them. This luxury of choice did not always exist for African Americans in the South and mid-Atlantic, where pawpaws grow abundantly, who were subject to the privations of first slavery and then Jim Crow. Pawpaws were seen as a delicious and nutritious wild food. African Americans in the South were not the only people to appreciate pawpaws. Common names such as 'hillbilly banana' or ‘poor man’s banana’ speak to the association of pawpaws with the poor white settlers of the South and Appalachia.
The seeds of the pawpaw’s current renaissance began to germinate in 1915 with a national contest sponsored by the American Genetics Society. A prize of $50 was offered for the best-tasting pawpaw. Submissions were sent from around the pawpaw region. From the mid 20th century onwards, a few devoted pawpaw enthusiasts worked to collect superior plants from the wild and began to cross these. The improved, though far from perfect, varieties of today originate from these efforts.
In 2016, it seems as if the pawpaw is on the cusp of broader recognition and enjoyment. Last year saw the publication of Pawpaw: In Search of America’s Forgotten Fruit, the first full-length book devoted to the fruit and its resurgence. A recent article in Modern Farmer magazine described pawpaws as "the trendiest fruit you've never heard of." The article further tantalized the reader with a promise of a delicious tropical fruit cocktail, and described the taste of pawpaws as "a cross between a mango and a banana."
The fruit must be eaten fresh; it spoils within a few days of picking if not properly refrigerated. The pulp can be used in baking and ice cream, and also to flavor beer. Craft distillers might also try experimenting with the fruit; 19th century references to potent pawpaw moonshine abound. So while the pawpaw may not be suited to be grown on a large commercial scale, the processing options for the home or small-scale market grower are many.
With so many positive characteristics, it’s a wonder that pawpaw cultivation isn’t more widespread. The reasons for this are intertwined with American history of race, class and changing consumer tastes. In 2016, with ever-increasing interest in organic and locally grown food, and using native plants in the landscape, it seems as if the pawpaw’s time has finally arrived again.