Tree of the Month, April 2024

Common Pawpaw, Custard Apple, Prairie Banana

Asimina triloba

by Martin (Mort) Schmidt for Simply Living

Young Pawpaw trees in fall. Photo by Mort Schmidt.

Pawpaw is the little tree with big leaves and fruit. In fact, Pawpaw has the largest edible fruit of Ohio’s native trees, even though it’s a small understory tree, often growing up from runners in thick, shrub-like patches. But despite its diminutive size, admirers of the Pawpaw include no less than George Washington, Thomas Jefferson, and Daniel Boone.

Pawpaw (Asimina triloba) leaves are among the largest leaves in Ohio’s forests, typically 7 to 10 inches long, and 3 to 5 inches wide. The leaves are obovate, and they are attached in a simple, alternate pattern. Ovate and obovate leaves are more or less egg-shaped, but ovate leaves are widest near the stem, while obovate leaves are widest near the tip. The leaves are pinnately veined. Pawpaw leaves are similar in shape and size to the leaflets of Shagbark Hickory, but Pawpaw leaves have entire (smooth) edges, while Shagbark leaflets have teeth. Also, Shagbark leaves are pinnately compound and occur in groups of 5 leaflets per stem. Pawpaws are easily recognized in winter by their small, flexible terminal buds that resemble an artist’s paint brush. And Pawpaw trees are vastly smaller than mature Shagbark Hickories, and have far smoother bark.

Left to right – Alternate leaf arrangement, opposite leaf arrangement, pinnate veins, palmate veins. Pawpaw has alternately-arranged, pinnately-veined leaves. Illustrations by Mort Schmidt.
Left to right – Pawpaw leaves, Shagbark Hickory leaves, Pawpaw bud. Notice that Pawpaw and Shagbark have similar leaf shapes and sizes, but Pawpaw leaves lack teeth, and Shagbark leaflets occur in groups of five to make a compound leaf. Photos by Mort Schmidt.

The lovely Pawpaw flower is instantly recognizable by its burgundy color and the presence of three lobes, from which it gets its Latin name, A. triloba. Pawpaws in Central Ohio bloom in April, and a good place to observe Pawpaw blossoms in the Columbus, Ohio area is on the Brookside and the Overlook trails at Blendon Woods Metro Park. The flowers are “perfect”, meaning that they are hermaphroditic, and every flower contains all of the male and female parts needed for pollination and seed production. The flowers, like the crushed leaves, have a disagreeable odor, but one that attracts pollinating flies and beetles. 

The Pawpaw is best known for its fruit. When Europeans first saw the Pawpaw, they assumed that its fruit was related to papaya, and gave it a similar name. The oblong Pawpaw fruit is approximately 3 to 5 inches long, making it the largest edible tree fruit native to Ohio. The fruit contains a soft pulp similar to custard and a number of large brown seeds. Some people relish Papaya fruit, but others dislike it. While Pawpaw is an understory tree and normally lives in heavy shade, they can be prolific fruit producers when transplanted into open sun. There were plans to plant Pawpaw plantations in the 1800s, but because of the fruit’s short shelf life and abundant seeds, Pawpaws were not commercially viable. Furthermore, Pawpaws are picky pollinators and will not pollinate themselves or close relatives. And a Pawpaw thicket often arises from a single root system, making it all the harder to obtain pollen from an unrelated tree. Perhaps Pawpaws have perfect flowers to maximize the odds of reproduction – they can’t self-pollinate, but they can serve as male or female if a suitable partner becomes available. Pawpaw seeds are disseminated primarily by mammals, because they are too large to be ingested by birds. But aside from primates, most mammals have limited color vision, and they evaluate fruits and vegetables on the basis of odor, not color. Consequently, Pawpaws don’t need to change color as they ripen, and they remain green to maximize photosynthesis. 

Pawpaw flower and fruit. Photos by Mort Schmidt.

Pawpaws grow to a height of 30 feet or less with a trunk diameter of under 8 inches, but Ohio’s Champion, located in Franklin County, has a height of 54 feet, a trunk diameter of 6 inches, and a crown width of 23 feet. The light gray bark is fairly smooth, with small warty lenticels. A distinctive trait that often stands out on Pawpaws is the presence of bulges at the base of branches. possibly to strengthen an otherwise weak wood.  

ID SUMMARY: Large, smooth-edged, obovate, simple leaves. Naked, soft winter buds resembling paint brushes.

Pawpaw bark. Notice thickening at base of branches. Photo by Mort Schmidt.

Pawpaw belongs to the family Annonaceae, which, except for the genus Asimina, is limited to the American tropics and subtropics. A. triloba is the northernmost species of pawpaw, and the most widespread. (I’m using capitalized “Pawpaw” for Asimina triloba, and “pawpaw” for other members of the genus Asimina). The seven other pawpaws are limited to the southern states, primarily Florida, Alabama, Georgia, and Arkansas, and they are rarely or never larger than shrubs. Lucy Braun’s The Woody Plants of Ohio indicates that Pawpaw occurs in most of Ohio’s counties, except for a few in the north-central part of the state. Pawpaws require rich, moist, but well-drained soil, often growing on hillsides and bottomlands.

Asimina triloba range map. Image from U.S. Geological Survey.

Pawpaw wood has little commercial value due to the tree’s small size, and limited information is available regarding its properties. The Wood Database has no hardness or density data for Pawpaw, but Harriet L. Keeler’s Our Native Trees indicates that Pawpaw has a density of 0.40 g/cc, compared to a median 0.64 g/cc on my list of 73 Ohio trees. Wood density correlates well with hardness, and Pawpaw’s density is similar to that of yellow Buckeye (Aesculus octandra), one of Ohio’s several softest woods (even softer than some conifer wood, despite the fact that conifers are regarded as softwoods and leafed trees as hardwoods). Most sources say that Pawpaw has low rot resistance, but its softness makes it suitable for carving. Some survivalist websites indicate that the soft wood is useful for starting friction fires and that the inner bark makes good tinder.

Pawpaw fruits have a small but loyal following, and are made into jams and jellies, pies, and chutneys. According to the University of Kentucky College of Agriculture, Food, and Environment, “It is an excellent source of vitamins A and C, and is high in unsaturated fats, proteins and carbohydrates. Pawpaws contain more potassium, phosphorus, magnesium and sulfur than apples, grapes or peaches. Extract from pawpaw can overcome the ability of some cancer cells to reject chemotherapy.” 

William Clark’s journal from the Lewis and Clark expedition said that “By Sept. 18 [1806], the party was within 150 miles of the settlements. It had run entirely out of provisions and trade goods… There were plenty of ripe plums, which the men called ‘pawpaws.’ Gathering a few bushels was the work of a few minutes only. The men told the captains ‘they could live very well on the pawpaws.’” Unfortunately, some men on the Lewis and Clark expedition suffered after rubbing their eyes while picking Pawpaws. The leaves and bark not only smell bad when bruised, they contain chemicals that repel insects and are toxic to many of them. Early settlers crushed the seeds of Pawpaw and rubbed it into their hair to eliminate head lice. This may also explain why Pawpaw trees are disease resistant, and deer don’t browse on the leaves and bark. According to the Native American Ethnobotany Database, the Cherokee and Iroquois peoples consumed lots of Pawpaw fruit, especially after drying it for storage. The Cherokee also used the inner bark to make a strong fiber for rope and fishnets. 

Pawpaws are an important source of food for wildlife. In fact, the leaves of Asimina triloba are the exclusive food of the Zebra Swallowtail butterfly (Eurytides marcellus) and the Pawpaw Sphinx moth (Dolba hyloeus). The large fruits are consumed by deer, fox, squirrels, racoons, skunks, and turtles. Birds also peck at the fruit, but they do not eat and distribute the large seeds. 

Unlike oak, Pawpaw isn’t the kind of tree that invites admiration, let alone worship. Pawpaws aren’t surrounded by the folklore and legends that make some trees official State Trees and tie other trees to biblical events. But according to the Missouri Department of Conservation, Pawpaw is connected to the famous Hatfield and McCoy feud. It says, “A historical marker near Buskirk, Kentucky, recalls the fatal Pawpaw Tree Incident. It reads: ‘This episode is the result of an August 1882 election-day fight. Tolbert, a son of Randolph McCoy, exchanged heated words with Ellison Hatfield, which started a fight. Tolbert, Pharmer and Randolph McCoy Jr. stabbed Ellison to death. Later the three brothers were captured by the Hatfield clan, tied to pawpaw trees, and shot in retaliation.’” 

You might learn that you enjoy Pawpaw fruit, and if not, you can at least appreciate the exotic, tropical-looking leaves of this small tree. 

Photo by Mort Schmidt.

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You can also listen to my talks on Ohio Broadleaf Tree Identification on YouTube, Part 1 and Part 2

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