PUSHING THE BORDERS

a couple years ago i started crossing the common fig, ficus carica, with other species. here's a list of my crosses sorted from oldest to newest...

ficus opposita x carica
ficus fraseri x carica
ficus ulmifolia x carica
ficus racemosa x carica
ficus aspera x carica
ficus lutea x carica
ficus sycomorus x carica

here are some pics

i live in los angeles but a year ago i purchased a 10 acre orange grove in central florida (sebring) to grow out and test my hybrids. my hybrids will help carica migrate south towards the tropics, but they will also help tropical species migrate north towards the temperates.

ficus pollination is so easy even a caveman could do it. well, i'm not sure if that's true. but when our ancestors were in africa they started migrating north, and it got colder and colder. it was pretty cold, at least compared to africa, by the time they reached southern europe. it would have taken them a million years to adapt to the colder climate but fortunately they didn't need to reinvent the wheel, since it had already been invented by neanderthals, who'd been living in southern europe long enough to develop cold adaptations like body hair. they were kind enough to share these adaptations with our ancestors, who then used them to leapfrog past the neanderthals. based on dna testing, barely any neanderthal dna migrated south, most of it migrated north and east and west.

nothing is more ironic than for people who are hybrids of sapiens and neanderthalensis to underestimate the potential benefits of adaptive introgression. naturally the benefits aren't guaranteed. if carica is crossed with all the other 800+ ficus species, each hybrid won't be equally vigorous or fertile. perhaps more than half of the hybrids would suffer from outbreeding depression to some degree, which is why the existence of ficus lutea x carica was limited to a small root that emerged from a seed. ficus lutea is in the subgenus urostigma, along with all the commonly grown ficus, except for carica and pumila.

back to the question of whether a caveman could cross-pollinate ficus. the process is actually fairly straightforward. i collect ripe male carica figs, cut them in half horizontally, set them cut side up overnight, tap out the pollen, mix it with water, suck it up into a syringe, and inject it into the figs of other species. but each step involves one, two, three or more details, that perhaps aren't so "minor".

from my perspective, the most important and fascinating aspect of ficus hybridization is the economic aspect. let's say that i put one of my hybrids on figbid. how much does it sell for?

a. $1
b. $1,000,000

in the first case, virtually nobody else would have an economic incentive to make more fig hybrids. the 2nd case would be an entirely different story... everybody and their great aunt would have a very big economic incentive to make more fig hybrids, and the market would quickly be flooded.

what would a flood of fig hybrids look like? currently the world spends way more money on ornamental ficus than edible ficus. maybe there would be far more demand for a cross between elastica and lyrata (both in the subgenus urostigma) than for any carica cross.

20 years ago i would have been happy to settle for a pretty face, such as ficus dammaropsis. if someone had asked me if its figs were edible i would have said something like, "who cares if its figs are edible, look at those gorgeous leaves!" nowadays i'm more greedy. a pretty face isn't enough, i also want substance. i want the ficus equivalent of monstera deliciosa. it has giant gorgeous leaves and, as its name implies, it also has really delicious fruit. admittedly if you eat it wrong you could die (i'm exaggerating a bit). i want the ficus equivalent of chrysophyllum imperiale. is it unreasonable for me to want this? naturally i really want ficus auriculata 'schokman'.

the biggest problem with the world is really simple. to understand the problem just think about botanic gardens. we all love botanic gardens, right? imagine if near the entrance of a botanic garden there were three donation boxes...

1. ornamentals
2. edibles
3. ornamental edibles

how much money would visitors put into each box? we don't know. we don't care to know? this is the biggest problem with the world.

everyone thinks they understand what it means to "be considerate". but how can any botanic garden truly be considerate of others when it doesn't know what's truly most important to others? naturally this applies to all organizations, communities and groups.

my friend don hodel has been planting rare ficus in public parks in his area (long beach, ca), with permission from the city. is he being considerate? it depends on whether you ask a ficus fanatic or a hungry person. i've been sharing my ficus hybrid seedlings with him and then ideally a ficus fanatic and a hungry person would both say that he's being considerate. this is of course my personal version of "ideal". if each public park website had a "donation survey" on it, then we'd all see and know the public's true version of "ideal".

when a "thumbs up survey" was used to name a $300 million dollar british ship, the public's version of an "ideal" name was "boaty mcboatface". what would the "ideal" name have been if a donation survey had been used instead? we don't know. we don't care to know? again, this is the biggest problem with the world. nothing has a more adverse effect on the supply of plants and everything else we love.

there are dozens of movies about fictitious superheros like spiderman and the incredible hulk. but where's the equivalent big budget movie about real life superheroes like luther burbank and george washington carver? movies are digital goods, which means that they can be easily copied. the possibility of pirating is what keeps movies cheap. this might sound good, except it means that producers cater to the masses. as a result, the public's version of an "ideal" superhero is batman instead of burbank. it would be a vastly different story with donation surveys. participants wouldn't be buying the movies, they would be spending their money to elevate the most valuable ones.

donation surveys are admittedly unfair in the sense that kids would have far less influence than adults. but when you're entering a botanic garden, and there aren't any donation boxes to choose from, then your money is less useful to you than it should be. consider the extreme example of living in a world with no plants for sale. for us plant lovers, a dollar would be a lot less valuable, since there'd be no nurseries to spend it in. by this same logic, the more nurseries, and botanic gardens, and public parks, and plant societies, and plant forums with donation surveys, the more useful and valuable our money. we'd have far more opportunities to use our money to credibly communicate which plants are most important to us, which would make it vastly easier for others to be considerate of our plant preferences and priorities.

supply and demand isn't a very difficult concept. the trick is understanding that supply is a function of demand. what's the demand for things that can't be bought? my ficus hybrids aren't for sale, so they can't be bought. therefore, "buying" clearly isn't always effective at revealing demand. this is exactly what makes donation surveys so useful. they can be used to reveal the (relative) demand for virtually anything. as a direct result, the supply would be infinitely improved.

Thank you for your interesting, detailed and entertaining account. This is a fascinating experiment and I think very sensible to look at an edible crop whose cultivation can extend into a wider range.

I'm a big fan of figs of Ficus carica, as well as the species grown purely for ornamental use. I know there's a carica hybrid with pumila, but I'm fairly sure it's just a novelty (?).

I'd love to try growing some hybrid Ficus which produced fruit in the Cornish climate so will follow your progress.

Good luck with some of those seedlings. I guess you can also try crossing the various species with the many carica cultivars?

"when a "thumbs up survey" was used to name a $300 million dollar british ship, the public's version of an "ideal" name was "boaty mcboatface". what would the "ideal" name have been if a donation survey had been used instead? we don't know. we don't care to know? "
Yet it was named the Sir David Attenborough to wide spread public acclaim.

robsta, you're very welcome, glad you appreciated it. here's a ficus pumila x carica...



i randomly found this at a local nursery (lincoln ave nursery) on 10 sept 2020. the label said carica x pumila and it blew my mind. how could an evergreen vine from asia possibly be compatible with a deciduous tree from the mediterranean?! i assumed that a very confused wasp was responsible. it wasn't until a year later, when i mentioned this cross to my friend randy baldwin, who is a living plant encyclopedia, that i learned that this cross had actually been made by a person... ira condit. again my mind was blown. for all the decades that i'd been collecting ficus i had firmly believed that it was impossible to manually cross-pollinate them since the flowers are completely inaccessible. condit had proved that it was actually possible, and he documented his groundbreaking achievement in his 1950 paper... an interspecific hybrid in ficus. 1950!?? yet again my mind was blown.

by the time of condit's death in 1981, his landmark paper proving the possibility of manually crossing two ficus species had only been cited 5 times. by 2000 the citation had only gone up to 7 times. here are all the relevant quotes from each paper that cites condit's paper.

each citation was essentially a vote for condit's paper. so his paper was basically the opposite of "boaty mcboatface". it completely failed to win the popularity contest by which academic papers are judged. how many other buried academic treasures are there? probably countless. only way to unearth them all would be with a donation survey.

i kick myself for not buying the cross that i saw at lincoln ave nursery. a couple years ago when i saw this cross at a different nursery, i did buy it, but it turned out to be a different variety, much more spindly and much less willing to produce fruit. the one fruit it did produce wasn't naturally pollinated, and it wasn't parthenocarpic, so it didn't ripen.

here in california ficus pumila figs aren't naturally pollinated, so their figs never ripen, so they can't be eaten. in its native habitat i'm not sure if anyone regularly eats its ripe figs. there are quite a few different varieties. some look more edible than others.

i'm not sure how many times pumila x carica would have to be crossed back onto carica before carica's wasp was able to pollinate it. this would then result in a hybrid swarm with adaptive introgression.

on inaturalist i found this observation of a ficus carica growing on a wall in edinburgh uk. how did it get there? someone dropped a bit of imported fig on the ground, and a rat or bird ate it and pooped a seed on the wall? i actually started an inaturalist project for ficus growing on walls. here's the map for europe. you would have guessed that the carica wasp and carica would have gone up the coast of france, but perhaps the winds blow down the coast. the wasp is also in germany, but hard to say how much of germany it has colonized. its interesting to see observations of carica growing on walls in nertherlands and belgium.

do you grow carica? ever tried grafting it?

The example in Edinburgh could also have come about by a human eating a fig and wiping the residue off onto the wall either accidentally or deliberately. Given the sheerness of the wall it's a little difficult to see how a rat or bird could have got it there. Another possibility is an ant. If it had been on the top surface of the wall then rat or bird would be likely.
I'm surprised that no figs are reported ad growing on walls in Sheffield as there are 70 or more wild figs growing along the River Don stretching up to Doncaster. The River Don was used as a cooling water source for the various steel mills along it.
https://thedirt.news/fig-tree-forests-f ... -biscuits/

NigelJ, i've been meaning to thank you for sharing that sheffield story. its now one of my very favorite stories! the other day i stumbled on this 10 minute youtube video on the very same topic. there are quite a few factual errors in the video but it was still very enjoyable.

i'm pretty sure that the carica wasp could survive in milder parts of the uk. the main bottleneck is that they can only reproduce in male figs. barely anybody grows male figs since their figs are typically inedible.

for anyone particularly interested in figs, my friend in australia created a brand new fig forum. its more for fig nerds than the other fig forums. i'm really happy that there's a category for fig breeding.

just now i wondered about ficus pumila in the uk, so i searched inaturalist and found 10 results. one of the results included a pic of its fig! the fig is edible when its pollinated. recently i found this blog entry by a guy in japan who did a taste test of ficus pumila. the flesh looks delicious. but whats crazy cool is that he goes on to share pics of hybrid seedlings he made by putting pollen from ficus pumila into figs of ficus carica. this is the reverse of the cross made by condit 75 years ago.