Unusual fruit: Pawpaw (Asimina triloba)
I'll bet most Dave's Garden readers have never heard of pawpaw, much less tasted one. I'll also put money on the odds that if you live in the eastern half of the United States that there are pawpaw trees growing somewhere in your state.
picture of pawpaw fruit used by permission from WikimediaCommons
Attractive native North American tree
Pawpaw (Asimina triloba) is a cold-hardy, native American tree species most closely related to a tropical family of fruit trees (surprisingly not the family that includes Papaya.) Pawpaw is worth noting for its large, fragrant edible fruit, the largest fruit produced on native North American trees. Sometimes called false banana, I ‘d say pawpaw fruit looks more like a green mango that you've gently squeezed into a soft oblong. Pawpaw grows well throughout most of the humid eastern half of North America, a zone with the state of Kentucky at it's heart. Asimina triloba does require humidity to thrive. It's a relatively small, understory woodland tree that spreads by root suckers or by sprouting of the lima bean sized seeds in its fruit. The pawpaw tree has big. long oval leaves , and a slightly tropical overall form, with golden yellow fall foliage color. Pawpaw leaves are fragrant when crushed and not bothered by many insects or diseases.
Identifying wild pawpaw
Pawpaw has alternate, simple, smooth-margined leaves which are 8 to 10 inches long. Leaf shape is oval, broadest beyond the middle with a short point at the tip and short stalk. Trees are small with few, long branches and thin, warty bark. Unusual brown flowers with three triangular petals appear in spring before the leaves.
source: The Audubon Society Field Guide to North American Treees (Eastern Region)
Ripening late summer and into fall, pawpaw fruit is high in vitamin C and several essential minerals and amino acids, and has more protein than your usual fruits. Obviously, pawpaw is eaten fresh from the tree, but lots of sweet recipe ideas can be seen on the recipe webpage of the Kentucky Pawpaw Foundation (Pawpaw Zabaglione, anyone?) You probably missed, as I did, the recent pawpaw fest at the Dixie Classic Farmers Market in Winston-Salem North Carolina. The flavor and nutritious value of pawpaw was certainly appreciated early in the history of the continent. Native Americans are said to have cultivated the trees; European settlers valued them. The beautiful zebra swallowtail butterfly will be ecstatic if you bring pawpaw to your area. Leaves of the pawpaw are the sole food source for zebra swallowtail larvae. Pawpaw fruit is said to be tempting to many small mammals, including 2-legged ones.
Picky picky pawpaw
As much as you might wish to grow pawpaw, and much as it feels at home in humid, temperate landscapes, you may face a few early hurdles in actually getting pawpaw established on your property. One unusual challenge is figuring out how to grow the seedlings in shade yet provide full sun for the mature fruiting trees. If you are strictly interested in growing pawpaw for wildlife or novelty, and can get your hands on a ripe fruit, pawpaw will grow from seed pretty easily. A single tree will grow quite happily but is not likely to produce fruit. You'd be very wise to try and gather at least two fruits, from two different trees, to help in pollination. Clean the seeds and plant them immediately. Keep at least one seedling from each fruit, and protect those seedlings from strong sun for the first few years, and you should be good to go.
Digging up wild pawpaw suckers or seedlings is not recommended. Pawpaws are one of those species that form a long taproot early, which is prone to breakage when transplanting. This is a good example to cite to discourage the digging of plants in the wild. In fact, New York and New Jersey wild pawpaw populations are in danger. Don't dig any wild pawpaws there!
Your pawpaw plantation dreams
Pawpaw connoisseurs will want a guarantee of fruit quality, and that hasn't proven possible growing pawpaw from seed. Luckily, there have been successful efforts in the last century to refine the cultivated stock of pawpaw. While pawpaw remains an uncommon fruit, a number of nurseries do sell young plants. Grafted, container grown trees are your best bet. A fair price is $20 to $40 for a well cared for, high-quality young pawpaw. You'll need at least two trees, as another glitch in the process of pawpaw fruit culture is poor pollination. While each flower contains all the necessary parts for full fertilization, interestingly, the female parts mature before the male ones. In addition, except possibly for a few cultivars, the trees are thought to be genetically incapable of fertilizing themselves even if the timing of various flowers on one tree do cooperate. Therefore, at least two separate plants are recommended to promote heavy fruit set. By the way, don't worry if bees seem uninterested in your pawpaw flowers. These chunky blooms are designed for beetle and fly pollination. If you notice a fragrance from the pawpaw blossoms it may not be a pleasant one.
Details on pawpaw cultivaton do not abound; the tree simply thrives in many "average" sites once it has passed its tender juvenile stage. Read the page linked here for the slightly fuller picture on proper pawpaw care. If luck is with you and fruit appears several years down the road, cross your fingers before tasting. Most who try pawpaw like it; some people can have allergic reactions to the fruit or its skin. (A skin rash can occur with pawpaw leaf contact as well.) The ripe to overripe transition happens quickly when the fruit is ready. Pawpaw is ripe when it softens slightly, becomes aromatic, and begins to change color. Further ripening brings dark spots and blackening, as on bananas. Ripe pawpaw fruit will hold under refrigeration for a couple of weeks. While pawpaw fruit has many past and present fans, the soft, sweet fruit is not universally loved by those who sample it. Maybe that's another reason pawpaw has not become a produce stand favorite despite its large native range.
Be the first on your block to grow Pawpaw!
After careful consideration, I'd have to say that pawpaw care is not harder than the culture needed to successfully grow most of the better known cultivated fruits. Asimina triloba would likely be a unique conversation piece in your garden, and your kitchen. The Purdue Center for New Crops and Plant Products says that pawpaw has "tremendous potential" as a "commercially important crop." Is pawpaw right for your site? Gardeners who understand pawpaw's basic requirements and early needs can enjoy this unusual, fruiting addition to a landscape.
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Kentucky State University Pawpaw Program
Purdue University The Center for New Crops and Plant Products FactSHEET Pawpaw
Virginia Cooperative Extension , Specialty Crop Profile: Pawpaw
Little, Elbert L. The Audubon Society Field Guide to North American Trees (Eastern Region). New York, Alfred A. Knopf, 1980.
postscript: While I have found several pawpaws growing in the wild, my search for actual fruiting patches has so far been, well, fruitless. I wll let you know if and when I get a chance to sample one!