Lonely PawPaw Seeks Cross-Pollination

Round about Mother's Day, my friend Karla received this email: "Lonely apple tree seeks similar for discreet short-term relationship. Afternoons preferred." Just in case there was any misunderstanding, some explanatory text was added: "My tree is blooming, for the first time; is yours? If so, can our trees make a date? Warm regards."

As it happened, her husband Steven was headed that very day to South Brunswick on a related mission, in search of pollen to satisfy the fruiting needs of another kind of fruit tree, the solitary pawpaw planted in their backyard some years ago that was now in full bloom. Though it had sprouted an additional trunk, it was still lonely, genetically speaking, and unlikely to set fruit unless visited by pollen from another pawpaw patch.

Thrust into the role of pollinator, Steven found himself at a distinct disadvantage. He had neither the wings to search the greater Princeton area for other pawpaw trees, nor sufficient olfactory apparatus to detect the subtle carrion-like odor pawpaw flowers use to attract pollinating flies. And since Google Maps does not (yet) provide directions to New Jersey's pawpaw patches, the search for prospective pawpaw mates required considerable research savvy. Even upon arrival at the best prospect he could find, the orchards at Rutgers, he still required the kindness of strangers to find the pawpaws amongst all the other fruit trees in the no-doubt vast plantings at Cook College.

This sort of matchmaking is becoming more common as the local food movement, perhaps abetted by backyards made sunnier by tree-toppling storms in recent years, prompts the planting of solitary fruit trees in cloistered backyards--peaches, apples, cherries, figs, persimmons, pears, and the occasional pawpaw--all with uncertain prospects for leading a healthy, promiscuous life of cross-pollination.

For those who know pawpaws only from the childhood lyric about a "pawpaw patch", they happen to be a native understory tree in the Annonaceae--a family of mostly tropical species. One relative of pawpaw grown by the Incas is touted as perhaps "the greatest fruit on the planet", with a taste combining mango and banana. Pawpaw, adapted to the north, offers a chance to grow tropical tastes in cold climes. Though delicious, its shelflife is short, which has thus far limited the pawpaw's commercial potential.

Thanks to the internet, I now know that the "way down yonder in the pawpaw patch" phrase that I've been carrying around in memory all these years comes from a boyscout song. I did not personally reach the status of boyscout, having earned my bobcat, wolf and bear badges in cubscouts only to lose momentum during a leadership void in that critical transition from cub to boyscout. The transition is called webelos, which stands for "we'll be loyal" scouts, a molting process that not everyone successfully completes.

If I had, I might have learned the complete lyrics for Pawpaw Patch, and known that "way down yonder in the pawpaw patch" answers the musical question "Where oh where oh where is Susie?" It matters where Susie is because she happens to be the "queen of Hawaii", which goes with the pawpaw's tropical family roots. If you ever go to Hawaii, you may encounter some of pawpaw's relatives, like the ylang ylang, soursop, and sugar apple. However, according to the song, you needn't go way down to Hawaii, because Susie will teach you to hulu way down yonder in the nearest pawpaw patch. If not completely distracted by Susie's hulu tutorials, the astute boyscout will note that "way down" and "patch" are descriptively correct, because the pawpaw tends to grow in rich bottomlands, and forms clones from its spreading roots.

There's another lingering pawpaw-related mystery knocking around in my memories. In my parents' Michigan backyard in the pre-internet 70s, a pawpaw sprang up spontaneously one year, grew into a patchlet of several stems, and after a few years began bearing flowers and a few fruit the size of a small mango. Where the pawpaw came from is a mystery, as was its capacity to bear fruit, because there was no known patch nearby, and the seeds looked much too large to navigate a bird's digestive tract. We didn't ask questions, however, because they were delicious. A bit of pollination assist with a cue tip may have helped with yield one year, which the raccoons and squirrels were grateful for.

Steven's recent research, empowered by the internet era, has delved far more deeply into the sexuality of a pawpaw. Way up yonder in this pawpaw post is a picture that Steven sent me of two pawpaw flowers, the green one not yet having acquired that lovely burgundy hue that flies are supposed to mistake for dead meat.

If a pawpaw flower were able to speak to its sexuality, it would say something like "I was female before I was male." Here to the left is a male flower, which is really a female flower a few days later. Looking closely, you can see a subtle difference. There are now yellow (male) anthers surrounding the green dot in the center (female stigma). The logic is that the anthers on any particular flower open up as the stigma is closing down, thereby preventing a flower from pollinating itself.

But that logic suggests that a tree with flowers in different phases could in fact pollinate itself, with pollen from one flower spreading to the next, and make fruit without importing pollen from elsewhere.

Still, the available information suggests that it helps to have cross pollination from one pawpaw patch to another, and that human-assisted pollination is often needed to make up for a lack of interest among the local flies.

Next year, Steven won't have to travel to South Brunswick in search of a "house of reputed pawpaws", because by chance I found a fine potential mate in the backyard of another friend, behind the Jewish center just a quarter mile away. It's a splendid specimen, thirty feet high, sporting perhaps a thousand flowers.

But pawpaw growers shouldn't have to depend on chance discovery. There needs to be an internet dating service for fruit trees. Sometimes it takes a village, or at least a good network.

Update, June 9: Just met a neighbor named Joe who has replaced the lawn in his side yard with four varieties of pawpaw and a lot of mulch. He says that wild pawpaws are common in Maryland, that raccoons and squirrels may be repelled by the bad-tasting skin of the fruit, and that it's easy to emerge from wild pawpaw patch with large buckets of fruit. I did not ask about any encounters with Susie, or if Marylanders are more adept at doing the hulu.


Some interesting links:

http://apiosinstitute.org/asimina-triloba-pawpaw

http://www.hort.purdue.edu/ext/ho-220.pdf

Finding Pawpaws in Paw Paw, Michigan

When the Lunar Octet, a latin/jazz band I've been in for 40 years, performed this past weekend in PawPaw, MI, a jazz naturalist like me was naturally curious about whether there are any pawpaws growing there. 

The town, named after the PawPaw River, which in turn was named by the indigenous people after the pawpaw trees that grew along it, has a population of about 3500.  Though the downtown preserves some historic feel, the town has not exactly embraced its namesake. Grapes ornament the town logo on the water tower and elsewhere, not pawpaws. 

Upon arrival, I asked my phone where I might find a pawpaw in Paw Paw, and was directed to the post office, where I navigated past redbuds and callery pears before finding this pawpaw tucked around the side. 

The tree had fruit, but none ripe as yet. I asked around, at the sandwich shop and down along the beautiful lake where we performed. Most people were unfamiliar with this native tree. The post office worker I ran into said he didn't know anything about pawpaw trees in PawPaw, except that he doesn't like the taste. 

The flavor of a pawpaw, a rich, creamy combination of mango, banana and pineapple is appealing to some but not everyone. Our host was more generous with her knowledge and assessment, mentioning a couple places the pawpaw grows in town, including at one of the schools.

The town of Pawpaw sprouted along the Territorial Road, one of the three main east-west routes of pioneer days. That history is documented next to the lake, but the native tree remains largely unknown and uncelebrated in a town that bears its name. 

My theory is that, since Asimina triloba primarily grows in floodplains, the pawpaw trees were lost when the river was dammed to make Maple Lake. Its fruit, with fragile skin and a taste less universally appreciated than other tropical-tasting fruits, resisted mass marketing. That, and the general drift away from plant knowledge, consigned the pawpaw to obscurity. 

Still, it remains a singular fruit, the only member of the tropical custard apple family, Annonaceae, to adapt to northern climates. And some of us still remember the song: "Way down yonder in the pawpaw patch"--a pawpaw patch that, in PawPaw, Michigan, became a lake with a lovely breeze to carry our music. 

Update: Turns out that, if you live in PawPaw Michigan, you'd have to drive to southern Indiana or Ohio to find a festival celebrating the pawpaw. PawPaw's festival celebrates grapes.

Sustainable PawPaw Liberation Service

As someone highly empathic towards plants, I woke up today sensing that something was amiss. Somewhere, a native pawpaw was being shaded out by a Norway maple. Now, I like Norway, and I like maples, but a Norway maple tends to sprout unasked along the fencelines of our fair town, then cast its over-the-top stifling shade upon all hapless plantlife that, through no fault of its own, happens to be growing nearby. Many plants suffer in silence. In fact, just about all of them do, if they happen to be suffering, and it's up to those of us bestowed with special powers, caring, and knowledge to act for their welfare. The situation is all the more dire when a pawpaw is not getting enough light to make flowers and bear that delicious tropical-tasting fruit.

As the founder of the Sustainable PawPaw Liberation Service, it's my job and perhaps solemn duty to rescue pawpaws in distress. A deep commitment to botanical justice and increased pawpaw productivity moves me at times like this to finally stop posing in front of my garage with my pawpaw liberation saw,

and put some mettle to the pedal. Useful tip: Riding while holding something in one hand is probably not a good idea, but if your hat looks alot like Lancelot's, or at least you're holding something that looks alot like a lance, you'll find that car drivers suddenly start showing some respect.

I arrived on the scene without a second to lose, although if I'd waited a week it probably wouldn't have made much difference. Just as I suspected, a friend's pawpaw was being heavily shaded by a Norway maple. The pawpaw's endearingly obovate leaves were literally, or at least laterally, crying out for sunshine.

Elsewhere in the yard, its faithful companion pawpaw, long liberated, kissed by sunshine and now thirty feet high, had borne most nobly a thousand blooms this spring just past, yet for lack of a companion to cross--pollinate with, it had not one fruit to show for it. Clearly, action was needed so that this fine upstanding couple might share their pollen and bear most heavily many a pawpaw in years to come.

A few deft strokes of the pawpaw liberation saw were all that was needed to, well, at least get the lowest maple branch out of the way. You can see a little gap in the canopy where the sun can shine through. A higher branch will require even more chivalry, and a good ladder.

Though logistics prevented a fully accomplished mission, the intervention may still bear fruit.

PawPaw Patches Proliferate in Princeton

My friend Stan, who has a knack for collecting and growing out seed of local fruit trees, gave me about twenty pawpaws (Asimina triloba) he grew from local populations of this remarkable native species. Though adapted to the north, the pawpaw bears a fruit reminiscent of mango. Hard to store and ship, the fruit has proven hard to turn into a cash crop, so it remains at the margins of our diets and awareness.

I delivered three to Mountain Lakes, for planting there, then called up my friend and author-of-note Clifford Zink over at Harrison Street Park, to see about starting a pawpaw patch over there.

Last month, we planted three in a swale that receives water from a nearby parking lot--a good urban version of the floodplains that are the pawpaw's preferred habitat.

Around the same time, Bill Sachs gave me some white cedars and hemlocks he'd grown in his backyard. Bill has been leading efforts in town to bring back the native chestnut and butternut. Since white cedars are adapted to swamps, two of them ended up in the Princeton High School ecolab wetland, thanks to environmental science teacher Tim Anderson and his students.

Most of the pawpaws are being saved for planting a pawpaw patch out at the Veblen House site, part of a PawPaw Patch Planting Party, public invited, tentatively scheduled for the first weekend of the new year, El Nino weather permitting.

(Other pawpaw posts can be found by typing pawpaw into the search box at the top of this website.)

Sunday Tour/Workday at Veblen House Grounds

Stop by the Veblen House this Sunday, March 13, 2-5pm, where we'll be having a work day and can give you a tour of the grounds. The tour consists of telling stories about the many features of the grounds, and the remarkable people who lived there. Some projects are putting protective cages around the pawpaw seedlings in the pawpaw patch, clearing sticks and brush from ditches, and digging shallow diversions to divert runoff from the trails.

We'll provide cider and cookies, and I'll have "live stakes" of native elderberry, buttonbush and silky dogwood for anyone wishing to take one home to grow in the yard. Kids welcome.

Directions: Reach the Veblen House by entering the gravel driveway across from 443 Herrontown Road in Princeton (look for Rotary sign wrapped around a tree), or by taking the trail from the Herrontown Woods parking lot up to the farm cottage (cedar shingle siding) and taking a right through the fence. Veblen House appears as a small white square on this map, north of the parking lot.

Local PawPaws Ripe

For anyone who hasn't tried pawpaw--our northern representative of a largely tropical family of fruits in the Annonaceae--the Whole Earth Center has some in stock from a local supplier. The harvest only lasts a couple weeks each year, according to one employee. Pawpaws have a short shelf life, and bruise easily, which has long hampered efforts to market them in anything beyond a small scale, local fashion.

I bought one and shared it with my daughter, who had never had one. She said it tastes like a combination of mango and kiwi. Delicious.

You can type "pawpaw" into the search box at the top of this blog to find a couple previous posts on the subject.

Lose a Tiger(lily), Gain a Paw(paw)

"Come see our tiger lilies!", I was told at a party recently. Naturalists get this sort of invitation now and then. I was a bit skeptical that they were tiger lilies, though, because there was mention of spreading,

and the only tiger lilies I've come across in Princeton are the ones in this photo, behind Conte's. Nevertheless, I took them up on the invitation--my interest piqued by the owner's enthusiasm about these lilies.

Sure enough, they proved to be daylilies, a step above the humble, unimproved orange found in abundance in my yard and many others, but daylilies nonetheless.

Now, I didn't really want to be a bearer of bad news, or even not-so-bad news, since a day lily is still a lily, whose blooming is no less worthy of the owner's enthusiasm for lacking a tiger in the name. People's relationships with plants should not be taken lightly. The plant names that inhabit my brain in abundance tend to take up only the briefest of residencies in the minds of most others, falling away like leaves in a late October breeze.

So when a plant name lodges firmly and resonantly in someone's mind and heart, it's hard to point out that this plant that has come to be known so emphatically as a tiger lily is in fact a daylily. The flower itself is far from plain as day, but "day" can't compete with "tiger" for affection. Which day is the daylily named for? It could be a good day or a bad day, sunny or gloomy, we really don't know. There's no hint of wildness in a day. A day is a mere vessel to be filled with meaning, not a gloriously fearsome beast stalking your yard, fortunately in the benign form of a flower. As I weighed my options, a homeowner's connection to a plant, facilitated by a colorful name, hung in the balance. What to do?

Long a slave to truth, I sought at least to soften the news, by saying that all lilies that grow in Princeton with that classic orange color really should be deserving of the tiger lily name.

After all, with tigers all aprowl on campus, guarding various entryways, the Princeton University Tigers on one side of Nassau Street, Little Tigers on the other, and tiger stripes dominating the color schemes in parades and giftshops, doesn't tigerdom eventually seep into all things and people who reside here long enough? A certain fierceness, perhaps, lurking beneath the civilized demeanor. If nothing else, it manifests in a Princetonian's capacity to leap into the breach and spout copious, tenacious opinions at town hall meetings.

The owners seemed to take the news well enough. If daylilies they are, then daylilies it is, from here on out, though I could tell a bit of magic had fallen away from their front yard. We continued to the backyard, which had that minimally managed grow-what-will look. I was tempted, because of the ground made wet by a very active sump pump--the house having been built on what was likely once a tributary of Harry's Brook--to recommend various of the floodplain flowers that would prosper there, but resisted. There was something soulful and relaxing in this yard that wasn't trying to be anything other than what it is, shaded by Norway Maples and backed by a thick stand of bamboo that obscured the condos just beyond the fence.

I looked around and saw the usual, a pokeweed here, a rose of sharon there, Japanese honeysuckle growing on the fence, and was going to go back to conversation when I happened to look up and saw, what's this? Pawpaws? The northern growing tropical fruit that many of us covet, many have planted, and many must now wait years for any chance of a crop. And here it was, a mature tree loaded with fruit, prospering unbeknownst to anyone in a grow-what-will garden.

I pointed it out, proud of my find, hoping it might make amends for the loss of a tiger lily. Surely, the taste on the tongue of the word "tiger" cannot compare to the lush, yellow, mango-like pulp of a pawpaw. Only later did I realize that I had taken away a tiger, but left them at least with a paw or two. Who knows, maybe it's the distant descendant of the lost pawpaw patch of Harry's Brook, where sabertooth tigers stalked the megafauna of yester ice age.

Addendum: If you dare to walk right up to a tiger lily, you will see the spots on its petals and small black bulblets in the upper axils. The bulblets, if memory serves, can be plucked and planted, to make little tigers. 

Other lilies hereabouts are the towering native Turk's Cap lilies at Morven Gardens, 

with their whorled leaves,

and another, the most truly wild but also the shortest, flying below the deers' radar out at the Mercer Meadows prairie restoration on Cold Soil Road. 

Alert: Monitoring for Lesser Celandine

Memory was finally jogged that this is the time of year to be scouting Princeton's natural areas for the dreaded Ficaria verna, a.k.a. fig buttercup, or lesser celandine. Dreaded because it has an alluring yellow flower that makes one want to leave it be when it starts showing up in the yard or local preserves, but then quietly takes over, paving whole valleys. Pettoranello Gardens is carpeted with the plant. In Durham, NC, I once tracked an infestation upstream to a homeowner's yard. He was greatly relieved to find out what plant had taken over his garden, and proceeded over the next several years to completely eliminate it. Unfortunately, by then the plant had spread far downstream and would transform a whole watershed, from one small infestation in someone's yard. He was, however, able to remove some he had put in his son's yard elsewhere in town, before it had a chance to spread downstream. This is why it's so important to get the word out about these highly deceptive species.

When I was working at Mountain Lakes, I'd walk the valley leading down from Stuart School, searching for any small patches that could be eradicated before they expanded beyond remedy. It's satisfying to be able to nip invasions in the bud. Now that my focus is Herrontown Woods, the spring ritual is playing out there. Yesterday's walk yielded no sightings until the very end, when I checked the pawpaw patch we planted New Year's weekend, and headed back through the woods towards the parking lot. There, right where the groundwater seeps out of the ground in what originally may have been a primitive septic system, was a patch of lesser celandine. Already, it has spread down the ditch about fifty feet, but is still of a size that we can eradicate it before it spreads down the valley, beyond control.

Control options can be found at this link. A comparison of lesser celandine with other yellow spring flowers, such as marsh marigold and celandine poppy, can be found here. If possible, avoid hiking through an area with lesser celandine--there's a risk of inadvertently spreading it into new areas in the treads of your shoes.

Strangler Figs: Airborne Roots and Flying Buttresses

Coconut Grove, FL, where I was fortunate to spend a week with family for the holidays, is named after its palm trees, but the tree that will catch your eye more than any other is the strangler fig. 

How silly we are, these extraordinary trees seem to say, to think that trees should start life on the ground, have only one trunk, make their flowers seen and keep their roots tidily hidden. 

The strangler fig's logic is clever. How can a new tree survive in a tropical forest where existing trees cast deep shade and have a lock on soil nutrients? It starts its life as if on stilts, as an epiphyte high in the canopy, sprouting on the trunk of another tree. Oftentimes, the seeds, freshly digested by a bird, catch in the rough bark of a live oak, or a cabbage palm. Declaring itself improbably independent of nutrition from mother earth, it lives at first on air and rain, growing stems skyward and roots earthwards. When the roots reach the ground, the strangler fig's growth accelerates. The above ground portions turn into multiple trunks that envelope the host tree. That embrace can ultimately prove lethal, providing the strangler fig with a convenient supply of additional nutrients as the host tree rots away. 

 

More and more roots are sent downward, each one turning into yet another trunk when the roots reach the ground. Surely if one trunk is good, then many must be much better. The result brings to mind a cathedral replete with flying buttresses. 

The result of all this free-thinking, or if not thinking, then free-doing, is a tree you can walk through. 

This old beech tree in the Institute Woods in Princeton achieves a somewhat similar effect, though it's just one trunk that has rotted through. A closer equivalent in our forests is achieved in a more covert fashion. Trees like beech, sassafras, pawpaw, black locust, aspen, and the blackhaw Viburnum sprout new trunks as their roots spread underground, creating what appears to be a grove of trees that is in fact one individual.

Wikipedia lists 13 different species of strangler fig around the world. This one at Barnacle Historic State Park is the native Ficus aurea, whose fruits the sign says are edible. 

I'm guessing that many of the other strangler figs--those with myriad trunks like this impressive specimen at the University of Miami--are banyan trees from India.

On the left in this photo you can see some aerial roots growing towards the ground. 

Here's a closeup of a cluster of soil-seeking roots growing downward from a limb--another tree trunk in the making.

What little bamboo I saw in Coconut Grove paled in comparison to the expansionist aims of strangler figs. 

This fig appears ready to eat the pavement, 

while others drape themselves over walls, 

or probe the local infrastructure.

This strangler fig was so bold as to break into a tiger's cage.

Fortunately, there's no tiger living there now, just a couple of chickens. 

I forgot to mention the hidden flowers, which are borne inside the fruit and accessed only by a tiny wasp. Each species of fig has its own specialized species of fig wasp to fertilize it. For more reading, and some cool photos of just how tiny those wasps are, here's an interesting post. This Forest Service post describes the mutualistic relationship between the wasp and the tree, and says the U.S. has only two species of native fig. 

For anyone headed down Florida way, a good example of a banyan tree can be found at the Marjory Stoneman Douglas Minipark, named after the famed activist and author of The Everglades: River of Grass.