Article from the Tropical Fruit News magazine of the Miami Rare Fruit Council International
talk by Har Mahdeem




The Pawpaw and Its Relatives

Reported by Bob Sarnack

Har Mahdeem is a longtime memberof the RFCI, and is valued especially for his expertise on the many members of the Annonaceae family. With this presentation, he brings to light many interesting and little-know facts on a cherimoya relative that has the cachet of a tropical fruit but is a ancient native North American that now is being rediscovered all over the United States.

In the Annonaceae, the Custard Apple family, there may be as many as 2,500 species. Most of those do not produce edible fruits but a great many of them do. About a fifth of those species are in several genera; of those I am mentioning first, one flower produces on fruit. We have the Annona" the Rollinia, the Raimondia, the Annonidium, and the Monodora -- in each genus, one flower produces one fruit. But the majority of the species in the Annonaceae family have a different arrangement: one flower produces a cluster offruitlets. There are something like 60 genera in the family that do this; of those genera, about half of those has at least one species that produces edible fruit. There are a few others that produce edible flowers or edible seeds. Tonight we will be speaking about one genus from the majority in the Annonaceae family in which one flower produces a cluster offruitlets, the Asimina genus, which has eight species, all in North America and most of them growing in the temperate zone ... very out of the ordinary for this family of plants.

"Most plants in the Annonaceae family are strictly tropical. There are some subtropical ones, and there are just a few that take cold weather. The Asimina genus has eight species. The one species which is important is Asimina triloba which is known in everyday language as Pawpaw. Now, don't confuse this with what they call 'pawpaws' down in Jamaica or over in Australia or other places where British-English speakers call papayas 'pawpaws'. Payayas have no relation whatsoever to the fruits which we are speaking about tonight. The Asimina triloba, the pawpaw can grow as far north as Ottawa, Ontario, Canada, so it's truly a cold weather species, There's one other species in the Asimina genus which produces a fruit that isn't much good for anything; Asimina parviflora which grows as far north as Virginia, Tennessee or Texas. It has a wide range starting from Florida. All of the other six species in the Asimina genus grow in Florida and a few of them on up into Southern Georgia. A couple of species are strictly here in Southern Florida. At least six of the species in the genus can take a good deal of cold weather. "It has been said many times, and I believe erroneously, the Asimina genus is the only one in the family that has cold-tolerant species. Annona glabra grows up at least as far as Cape Canaveral, so it is subject to frequent freezing.

There are a couple of species in the Rollinia genus that grow way down into South America, into Uruguay and Argentina; those take frequent freezing as well. Here in Florida again, we have one other genus in the family which is called Deeringothamnus. There are only two species in that genus; they both produce edible fruits, but the fruits are very small, the plants are very small and most people never see them. I've never seen one yet. A friend of mine know where to get them, and hopefully by the end of this year she will send me some seeds. She says the Deeringothamnus fruits have a delightful aroma and flavor, but the fruits are about peanut size. Here again we are speaking about a genus that produces a cluster of fruitlets from one flower. One species is found up near Daytona and Deland and the other is found near Naples. So one is sup-tropical and the other is temperate zone. "

Har began his slide presentation: "Until about four years ago I had never eaten a pawpaw. I heard about a man called Neal Peterson who ran the Pawpaw Foundation up in Washington D.C .. I called him one evening and asked how many of the tropical relatives of the pawpaw he had tried, and he said, "well I've had atemoya and cherimoya from the supermarket and guanabana nectar from a can." So I offered to send him some of the other species if he would send me pawpaw, because I had never tried pawpaws." His slide showed them nicely wrapped up in paper "with directions as to how to handle them ... They weren't too beautiful sort of green with some brown spots, (and) a wonderful smell. I've never smelled anything else that was better .. Here's what the look like inside .. usually two rows of seeds. Notice that the fruit is long rather than round and of course we are just looking at a fruitlet from a cluster. The pawpaw is also called the Nebraska banana, Michigan banana, Hoosier banana and so on. Some say that is smells and tastes a little bit like a banana. I don't think so, it's much better." He statesthatthe better varieties "taste something like the Cambodian mango or 'Nam Doc Mai' mango, or some better varieties of white sapote. So for those of you familiar with some of those, you can relate your taste buds. Those fruit taste much more like A. triloba, the northern pawpaw, than do bananas."

Har's next slides were of "Mr. Eric Dckworth from the town of San Mateo, Florida, right across the river from Palatka, up between Daytona and St. Augustine. He has the southernmost fruiting trees of pawpaw that I've heard of . They're all growing under the shade of other much taller trees. This was a bad fruit year for him. Some years he has had lots and lots of fruit. Your can see some the clusters of fruit. "


Har displayed a slide of "my father's yard up in Northeastern Alabama on Sand Mountain, up in 'snake handlers country'. He's not one of them. He has planted some pawpaw seeds there in his yard and put these little mushroom-shaped wooden umbrellas over them because pawpaw seedlings do require shade. Full Sunlight can kill them. These weren't doing very well though ... Here was another arrangement that he tried. He put the pipe in the planting hole before he planted the tree there. He pours the water and the fertilizer down the pipe so it can get down to where the pawpaw roots can make better use of it. Pawpaws have a long taproot if not started out in containers. Notice that these provided partial shade there. This setup definitely worked better than the wooden mushrooms. Here he has a grafted tree that he bought air mail from-a nursery and that's doing much better there.

Last September, Har attended the Pawpaw Foundation Conference at the Western Maryland Research and Education Center. Also in attendance were Crafton Clift, Dr. Carl Campbell ofTREC, and Dr. John Popenoe, former director of Fairchild Tropical Garden. "South Florida was very well represented there even though South Florida is completely out of the range of pawpaws. Bill Whitman has tried growing pawpaws at Bal Harbour. My boss (Gary Zill) and I have tried growing them in Boynton Beach and in Southern Palm Beach County, and quite a few other persons have tried growing pawpaws in southern Florida. So far, completely to no avail. They tend to grow well the first year, and then don't get enough cold weather to know when to wake up the following year, and maybe don't wake up at all or wait until July or August to put out their first leaves. Then it won't have those very long before it notices that the days are getting shorter instead of longer and drop those. After a couple of years of that they will just die. Also pawpaws are very susceptible to green leafhopper damage at least those two problems: dormancy and green leaf hopper problems. It's such a wonderful fruit though, that we're not giving up yet.

"This was an experimental planting at the research station for seeding evaluations. Neal Peterson got seeds from the best trees he could find all over the United States and planted them at this spot and two other spots I didn't get to see. He is the president of the Pawpaw Foundation and that is a volunteer job ... He makes a living as an economist for the United States Department of Agriculture in Washington D.C. Notice how close those trees are planted next to each other, about three feet in the row. Of course, if you were planting them where they would be in a more permanent location rather than for just evaluation you would plant them probable six, eight or maybe ten feet apart. Three feet apart just doesn't hack it. This was the last year for these trees. They are all going to be cut down. The best ones have been selected and grafted from and the whole grove is going to be cut down and other use made of the spot.

"One ofthe things that this was for was to bring the researchers together to decide the next stage of the research. The last I heard was there were 17 different universities and research centers that were going to make evaluation plantings identical to each other; three plants of each variety planted in different conditions in relation to the other varieties in the rows. I think they have something like 18 of the new selections from Neal Peterson's plantings and 10 or son named varieties that have been around for quite a while, and the idea is to choose the very best varieties from among these as grown in many different locations, observed by a whole bunch of professionals looking for a whole lot of details as far as productivity and adaptivity to different climates and the flavors that are most widely accepted. With pawpaws the flavor varies so much that this is very important. If you've tried pawpaw in the wild sometimes, as some of you from up north have, you may be looking at me as a crazy person because the one that you tried was awful. There are really a lot of terrible pawpaws in the wild. But when you get a superior selection then they are right up there with the best fruits in the world. So you need to keep this in mind if you tried pawpaw in the wild and don't like it, for sure don't give up on all of them, because there is a great deal of variation in taste, everything from turpentine and bitter to sweet, creamy and aromatic.

'These had been growing at this location for nine years, and you can see where one more year will bring the rows completely together unless they were pruned. You can see some of the differences in the leaves; some have deep veins and some of the leaves are quite smooth. I've never seen the flowers of the pawpaw, so I had to make due with taking a photo of a photo ... the flowers have six petals, are maroon colored, sort of corrugated and pretty good size. You see a cluster of young fruitlets with six or seven on that one ... on some trees a lot of those small fruitlets drop off. One of the things that Neal Peterson has decided is that he prefers one fruitlet, because (sometimes) the fruitlets don't all ripen at the same time. You pull one fruitlet off when it's ripe and gravity readjusts the positions of all the others, and two or three of them may fall off before they are at their best. But, if only one of the fruitlets is retained by the tree rather than a whole cluster, that one gets much larger, and of course when you pick it, you don't lose any others. Pawpaws are infamous for not producing very much. "

Har reported that at the conference, as the trees were going to be removed, "We all got to go through the experimental planting and try anything we wanted to, and bring home seeds and fruit. That's not what you can normally do at an experimental station but because this was at the end of the experiment we got to. (A slide showed) a tree that has so many fruit on it that the branches were breaking. They were really good too.


"Neal Peterson was telling us how he does the fruit evaluations. Notice the tee shirt he has on: 'I grow pawpaw and I vote!' The woman in the foreground is a poet and radio commentator in West Virginia and she's a board member of the Pawpaw Foundation. She does a lot of volunteer work there. She sang a folk song, a humorous song about a pepper and a pawpaw and all of their escapades. The woman behind her... was from the Department of Forestry in the People's Republic of China. 'This is Dr. Elaine Norman from Deland, Stetson University. She's .... familiar with Deeringothamnus and the Asimina species of northern Florida. She's donea lot of experiments in pollination, studying how pollination occurs in nature and ... hand (pollination): how many flowers you have to pollinate to get one to set a fruit, and also whether the different species will cross-pollinate. She's found that within each species, usually some fruit set will occur when only the plant's own pollen is available going from one flower to the next by insects. But, if there's another plant nearby of the same species, and pollen is brought from that, a much higher percentage of the flowers will set fruit. Whether this is the case with annonas. I don't know it is something to look into.

"Here you can see fruits from ... different trees; each (has) two numbers written on (it), the row number and the tree number. Here I have a photo of the most famous Annona and the most famous Asimina side by side; the cherimoya and the pawpaw. The one on the left is one fruit from one flower, and the one on the right is usually several fruitlets from one flower. So you will remember the tow major parts of the Annonaceae family; remember, a cluster of the fruitlets from one flowers is what most species ofthe family are like." Perfume, including the famous scent Chanel no. 5, is made from a member of the Annonaceae, the ylang-ylang (Cananga odorata). Its flowers are clusters of fruitlet. "I mention those because quite a few people have them here in South Florida. The fruits are absolutely terrible ...

" Har had a slide of "a scrub jay from the old coastal dunes" living in a reserve in northern Palm Beach County, near Juno Beach and Jupiter. The jays keep company with other endangered species, including Asimina tetramera, the four petaled pawpaw. "Incidentally, they don't all have four petals. In fact, on some plants you can see flowers with three petals and flowers with four petals side by side. actually, I should say sets of four petals on the' outside and four petals on the inside, for a total of six petals or eight petals depending on whether they're in groups of threes or fours." Har says that normally, members of this family have flowers with groups of three petals. "Some species only have one set of three petals, most have two sets." (Annona cherimola, the cherimoya, has an innerset of three petals so small "that you don't even notice them unless you use a magnifying glass or look very closely." Here you can see the outer set and inner set of petals on Asimina tetramera. I came back to see the flowers mature and the beetles had eaten them. So I've never seen a mature Asimina tetramera flower yet.

He had picture of one of the hot, bright dunes at reserve: "Right there in the middle is a plant of Asimina tetramera. The dune buggies have been driving right over it, perhaps including the park ranger's dune buggy ... Steve· Farnsworth did a survey of Asimina tetramera and he hound a little over 900 plants in three counties. It has been a protected species since then. It is illegal to dig one out or cut it down. Some architectural projects had to be severely revised, because someone noticed that there was (a four- petalled pawpaw) .. growing there and had to change the shape of the building to leave it alone. But this one is getting ridden right over. You can see the skinned up sides of the tree. There are rather ugly leaves on this particular one. It wasn't doing as well there. This was the fruit on it.. the first fruit of this species that I saw. I was very disappointed, but we'll see better ones. There are others growing here and there all over. You have to look pretty carefully to pick them out, because there are quite a few species of scrub oak and so on that have the same smallish, rounded leaf and they are easily confused.

"This is another one growing low with a lot of branches. I noticed that the few young ones that were around were in each case growing up from the shade of another bush. I didn't see any young ones starting out from a bare spot and that makes a lot of sense. Notice that this one has more decent-size fruits on it and several fruitlets to the cluster.. The sees of these germinated readily if planted fresh. It there was someone collecting the seeds from these and planting them right away, they would soon cease to be an endanger species. Apparently, whatever animals used to eat the fruit and then dig a hole somewhere and leave the seeds (with their other leavings) no longer exist, at least riot in sufficient numbers in these places, so the fruit stay where they fall from the plant. In most cases, there is nothing eating the fruits, and the dunes are just scorching hot and within about a week the seeds are no good any more. But, if you take them home and plant them, they grow just fine. A few of these plants have a reddish tinge to the fruit when they are immature, but when they ripen they are green like the others. I tried grafting some onto Annona montana (as) Crafton did (with his Asimina obovata x Asimina triloba) but my grafts didn't live long. You see a couple of tiny leaves down on the bottom there but the grafts didn't take.

"Here are some the planting experiments. I tried sixteen combinations which involved either frequent watering or little to no watering. Some were shaded and (some were in full sun, and there were) three different soil mixes. What did best was just plain sand with three Woodace fertilizer briquets in the bottom of each of these long citrus pots. It didn't seem to make an difference if they were in the sun or shade, wet or dry." He had "regular nursery planting soil with time release fertilizer mixed in; they seemed to get some fertilizer burn to start, but later on when the fertilizer was mostly washed out of the soil, they ended up growing reasonable well. As far as the flavor with these fruits, most of them are awful. Very bitter, justterrible. You wouldn't want to even touch your tongue to one, to be sure. But there were a few ... that were okay, (one tasted like yellow curry) and there was more than one flavor; some tasted like sweet watery avocados .. a couple tasted a little bit like a normal pawpaw ...

" He next discussed a pawpaw relative that grows in South Florida, Asimina reticulata. It is usually a small plant, with pretty white flowers." He was growing one from seeds sent by Crafton Clift from near Naples, and another "by the canal at Zill Nursery, right where the canal maintenance guts cut it down with a bush hog every two or three months. So it keeps coming up and flowering but it never fruits because the bush hog gets it every time. The purple area in the flower has a high protein content and it's especially designed to attract beetles and other bugs that will eat that area of the flower, right there by where 'the business area' is .. I've never tried this last species but I've heard that some of them are reasonable good. "



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Bibliography

Mahdeem, Har. "The Pawpaw and Its Relatives." tropicalfruitnews.org. Tropical Fruit News, Miami Rare Fruit Council. June. 1995. Vol. 29. No. 6. Web. 2 Mar. 2017.

Published 2 Mar. 2017 LR
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