Wednesday, September 2, 2015

Pawpaw

A nice clump of pawpaws nearing ripening under their huge, tropical-looking leaves. 

     North America's largest indigenous fruit is the Pawpaw, Asimina triloba, each attaining 3-6 inches in length when ripe. They are in the Custard-apple family Annonaceae, this genus being the Northern most members of this mostly tropical family. Like the Annonas and Cherimoyas I've eaten in Latin America, these too are quite edible. Their flavor is hard to describe, the consistency being like a banana, some people thinking they taste a bit like them, others comparing them to mangos and papayas. I don't think any of those is completely accurate though.

The Pawpaw is North America's largest indigenous fruit and the cold hardiest member of the custard-apple family. 

     Their most common name, Pawpaw or Paw-paw is thought to be derived from the word "papaya" with which they've been confused. They have numerous other names however, mostly due to their vague similarity to the banana: Wild Bananas, Michigan Bananas, Ozark Bananas, Hoosier Bananas, West Virginia Bananas, Kentucky Bananas, Prairie Bananas, Kansas Bananas, and Banango.

Flowers bloom when the leaves are still small and emerging.

      Pawpaws bloom in spring, usually just as their huge (up to 12 inches) tropical looking leaves start to grow. Being an understory tree or shrub, they need the large leaves to collect what little sunlight filters through the canopy. But blooming once the big leaves are out would obscure the flowers and interfere with pollination. Most of our spring blooming trees and shrubs thus do so when the leaves have not emerged or are just starting to grow for that reason.

The flower seen from underneath.

     The flowers are not your typical looking blooms either since they are attracting different types of pollinators. They lack the bright colors that many pollinators such as bees look for. Rather, they are likely pollinated by carrion flies, bottle flies, and carrion beetles. So they look (and often smell) like the color of meat: brown or maroon. They hang bell-like from the twigs, resembling the blooms of wild ginger, which often bloom underneath them at the same time and look a lot like them.
     Fruit set is often not very reliable. Not only do you need to attract unusual pollinators, but it is also believed that they are self-incompatible. Most of their reproduction is via suckers sprouting from the roots to grow a new tree. That means that a pawpaw patch may be all the same plant, all clones from the suckering roots. So you need pollen to be brought in from outside sources and you may get poor fruit set even with lots of flowers and a large colony of them. I've tried to hand pollinate them from the same clump and have not had good results.
     This, along with that the seeds may need 2-3 cold stratification periods (2-3 winters typically in the wild) to germinate, as well as that the fruits bruise and get over ripe easily, have made commercial production of this extremely cold hardy fruit problematic. People have tried (there's even a Pawpaw Foundation in Maryland trying to get commercial varieties that store and ship better) to make a business out of these, but have not often been successful. I've even heard of some people trying to keep orchards of pawpaw and hanging rotten meat when the trees are in bloom in the hopes of getting the right pollinators.

The flesh is soft and delicious, but does not store well and has large seeds.

     So production isn't easy. This is really too bad because the fruits are delicious! They are soft and juicy when properly ripe, with a strong tropical aroma. But getting them when just right and beating the wildlife to them is tough. Deer, bear, raccoons, possums, squirrels, mice, rats, voles, chipmunks, flying squirrels, turkey, and many other birds gobble them up. You need to wait until the fruit is a bit squishy, has a slight aroma, and is just starting to get yellowish with dark patches. Shaking a tree early in September around here sometimes results in a few good ones falling (and bruising themselves). They do not store well, especially if packed with other pawpaws or fruits which seems to make them ripen even faster. They might last a week if not bruised and refrigerated. A word of caution however, a small number of people have a slightly allergic reaction to the fruit skin, leaving a skin rash. My grandson falls into this category for example.
     The fruits also have a slight laxative effect, so take care how many you eat. A fellow naturalist related to me how he took scouts overnight camping one time and let them discover the joys of eating pawpaws. He warned them to just eat one or two apiece, but some of them, liking the pawpaws so much, harvested many more for use as night snacks, with predictable results.      

The large fruits have large seeds. Here's a handful from a single fruit.

     They have large seeds, but these are easy to remove. I often find them in the scat of other animals in the woods. They seem to sometimes be dispersed by the water as well, with most colonies growing near water ways.

Pawpaws have a golden Fall color, though the trees are short, they grow clumped together making for a showy look. 

     Though individual trees rarely get to 40', they are usually in clonal colonies. These pawpaw patches have yellow Fall color that makes them stand out. They also have fairly smooth, grey bark (though the older specimens get wartier as they age). The buds are also somewhat fuzzy, making them not too difficult to identify even in winter.

Pawpaw buds are hairy, which along with the smooth gray bark (sometimes a bit warty on bigger trees) make them fairly easy to identify even in winter.

The trunk of a Banango showing the start of the warts and bumps large specimen end up getting. 

     The trees have very large leaves that when crushed have a smell reminiscent of petroleum. Few things will actually eat the leaves (mules being one of them). This has resulted in their actually being one of the few native plants benefiting from the over population of deer we normally have in our region. They tend to eat other plants and seedlings first, selectively allowing pawpaws to survive better at least initially, though at the expense of other plant diversity.

The Michigan Banana is the sole larval host (food plant) for the Zebra Swallowtail Butterfly in our region. Here several males are puddling collecting salts and minerals. 

     One animal that really needs them though (other than for their delectable fruit) are Zebra Swallowtail Butterflies. Their caterpillars can feed on nothing else, pawpaws being their sole host plant. There are two species of Asimina (pawpaws) in the Northeast by the way, though the Dwarf (Small-fruited or Small-flowered) Pawpaw Asimina parviflora does not range into our DC region. Zebra Swallowtails are believed to retain some of the chemicals that make the plant distasteful and even toxic to other animals (mostly acetogenins) as a means of defense. You likely will never find these caterpillars on the pawpaws though, unless you visit the trees at night when the caterpillars climb out of the leaf duff and climb up to feed in safety from hungry birds. 
     The first European to note the use of the plant for food was DeSoto in the lower Mississippi in 1541. Since then many others have enjoyed them. It was claimed to be a favorite of George Washington who loved them when served chilled. Thomas Jefferson made sure to plant pawpaws on his plantation, and Lewis and Clark recorded eating them on their voyage of discovery, surviving off of them for 3 days. I've had both pawpaw bread and ice cream and can highly recommend them. Some enterprising folks have made jams and used them as substitutes for bananas in many dishes. I've even heard of wine being made from them, though have yet to taste that.
     Though  use of the huge fruits for food is obvious, there are many twists to their uses. The Iroquois not only made breads and cakes from them, but also sun dried the fruits for later use. The Cherokee not only ate them, but also used the inner bark fibers for rope, mats, and for stringing fish. 
     Francis Porcher, who wrote a Confederate treatise on using plants for many ethnobotanical purposes during the Civil War shortages, made some interesting notes on the use of the plant other than for food. Noting the chemical properties, he suggested using the juice from the unripe fruit to treat intestinal worms and the rinds to treat ulcers. He noted the poisonous seeds and how when crushed had been used to treat head lice. Porcher recorded that the leaves could be fed to hogs and poultry to tenderize them, claiming that freshly cut meat could be hung over the leaves to also tenderize them. The acetogenins that give the leaves their strong smell and make them distasteful to most wildlife are now being tested for use in treating tumors and as insecticides. 
     So you can see that there's a lot more to this plant than just its tasty fruit. But for me, that would be enough anyways. In 2009, Ohio declared the Pawpaw its official state native fruit. Not sure what took them so long, people have been enjoying pawpaws for such a long time. I know I look forward to visiting my favorite pawpaw patch very September. always trying to outguess the critters competing with me to get the Wild Bananas! 

My son Alex enjoys picking pawpaws almost as much as like eating them...

8 comments:

  1. I have found these along Billy Goat trail, along the Potomac in Maryland - though have yet to try them. Are they ripe at this time or has the season passed?

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  2. They are just starting to ripen in the Tidewater region of Virginia now, first week of September.
    Thanks, Alonso, this was great. I did not realize Zebra swallowtail cats were nocturnal!

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  3. Thanks for this information!! We have a few young Pawpaws growing in the woods next to our house, but they have yet to fruit. The blossoms are cool though & we just like having them around...

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  4. Thanks folks, the season will end very soon so get what you can...

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  6. We have them in Western PA and more out of the wildlife appeal I have 3 in my yards. I also used to travel back the last week of August to the C & O Canal to get some fruit because the variety there grows really large fruits.

    I think another name for them is "Dog Bananas" and even among the old timers they either love them or hate them. If you eat them green they will give you grief; I know this from some friends who made that mistake. If you go to Kentucky this time of the year the old timers sell them at roadside stands.

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  7. I had no idea Zebra Swallowtail caterpillars were nocturnal. That does explain why I've never found one, despite examining every pawpaw tree I see. I recently tasted some of the non-wild cultivars you mention, at Meadowside Nature Center's annual Pawpaw Festival. They were so good. I hope someday the popularity is high enough that we could at least buy frozen pulp at the market, or something like that. I always seem to miss the few days the wild ones are ripe since I'm competing against pretty much every single wild creature that lives nearby.

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  8. So, tell me, why the habit of the branches emerging directly below the above branches (or at ~60 degree angle)occur? Most tree branches spiral around the trunk to allow maximum availability to sunlight.

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