Ed, I haven't sat down and formalized any plans along these lines.

However, I have done a fair amount of informal underground cordoning this summer, with a number of different cultivars including Ronde de Bordeaux, Gino's Black, Takoma Violet, Aldo (Palermo Red), and Salem Dark among others.

By this I mean that I have bent down and buried ground level limbs anywhere from 1-4 inches below ground, extending the limb out in a straight line away from the tree trunk.

These limbs grow out of the trunk at or just above or below ground level. Preferably somewhat below. Over a period of days or weeks depending on how flexible these limbs are, I bend them into a shallow trench that I dig in the ground. My trenches so far are anywhere from 1 foot to 1 meter long, depending on how long the limb is. I leave a few buds/leaves near the tip of the limb and the limb itself curling up a few inches above ground. On most of these cordons, the tip starts to grow straight up as a vertical trunk removed typically a few feet from the main trunk.

My hope is that next summer quite a few new "trunks" will grow vertically between the main trunk and the tip trunk of the underground cordon. (Assuming the cordon survives the winter freeze. That may be a big assumption.) I assume that the cordon is rooting and therefore will be well rooted going into next spring, with plenty of live buds (protected by being just underground) for growing many new "trunks".

Next summer, I hope to pinch the tips of numerous new trunks, on each and every of these individual cordoned "trees," to produce plentiful fruit.

Some of this cordoning - live limb burial - I do on flat ground. Some of the cordoning is made easier by going up a slope. I don't know how it will all work, or if it will work at all. Theoretically is seems that it should work, but I've only now begun to attempt it.

Here is a Takoma Violet and an underground cordon stretching off to the right. The TV is in-ground, wintered over from last year. The pot that you see I cut and placed on about a month ago in an attempt to clone the trunk. I left the tip of the cordon curling up to poke out of the ground about a month ago. That tip has since grown a few inches, turning into a kind of trunk at a remove perhaps.
 
Similarly below - this is one Salem Dark tree put in ground this summer. I trained a ground level limb underground, and it now appears to be growing as a trunk at a remove there to the right.

Below, is a Hardy Chicago that I began to cordon underground then called it off and brought it back above ground. I both didn't have enough space there and the limb was too high above ground where it grows out of the trunk, I thought. So now it's merely a low growing near horizontal limb a bit above ground. I'm thinking of digging this tree up and putting it in a pot.
 
Below, more examples of young trees with a limb cordoned underground this summer and the tip growing up at a distance. Hopefully next summer numerous fruiting trunks will shoot up between the tip and the main trunk all along the underground cordon. Again, the sliced pots that you see are clone attempts, as these are young in-ground trees.

   
This is what I have been trying. I'm sure there are many different ways to try getting cordons underground. Maybe too there are more accurate words and phrases for this sort of technique than "underground cordon". I expect these to be underground rooting cordons, not rootless like above ground cordons.

You'll have to keep us posted on this Tony, interesting idea. Are you concerned about the cordons rooting and there being too many shoots? Or will you just thin the shoots as needed? I can't imagine they will only grow from those tips for very long, it'll start sprawling and crawling in no time at all since they look like happy, healthy plants.


ps: I see you have an enemy in Creeping Charlie as well. That stuff won't stay out of my beds, but it looks nice when it blooms in spring.

Yes, I added a note that I expect the cordons to root since they are underground. And thinning might well be necessary. 

Sometimes I battle with what you call Creeping Charlie a bit but it does serve as a kind of living mulch too and should compost in place nicely over the winter providing some nutrients for next year's fig trees I expect.

Looking forward to seeing how this progresses next year. I was going to do the above ground technique but if this works like you are planning then I will do this instead. Having more roots along the entire length of the "Cordon" can only be a good thing.

Tony, thanks for the excellent description of what you are doing.

I think the only drawback to what you are doing is that these roots start out pretty shallow.  If a whole cordon or stem was planted down a foot or more lower, it would likely be better protected.

Either way, eventually you will have a somewhat 'linear' mass of roots, with new stems emerging from within each time the winter is bad enough to kill the existing trunks.  OR just prune back to ground level every winter. 

This will probably only be worth doing with relatively early fruiting varieties here in the North. 

I might try doing one row of a step-over espalier and compare with a row of trees with the trunks planted deeper horizontally, if I can get enough growth on them to get several feet underground at one time.

Thank you, Tony. I appreciate the description and pics of this plan/concept. Please keep us posted on the findings this coming spring/summer with updates. Very interesting idea!

I appreciate all the interest. I look forward to continuing to monitor, expand, and vary these experiments.

In regard to this: "I think the only drawback to what you are doing is that these roots start out pretty shallow.  If a whole cordon or stem was planted down a foot or more lower, it would likely be better protected." 

In my zone 5 underground cordoning attempts this summer, I did go deeper than a few inches, as much as a foot deep or more.

The reason that I did not go deeper here in zone 6 is that I noticed during this very harsh past winter that very little if any wood damage seemed to occur even slightly underground. Essentially all the wood damage seemed to be to air exposed wood or to wood under a very thin amount of mulch. 

Of course, it's possible that shallow underground cordons will be different, be more susceptible to cold damage than any main trunk, and so in future years I might have to cordon deeper (if this technique is workable at all). However, another reason that I did not go deeper this year with the cordons is that I noticed when I took extra precautions last winter and mulched young tree trunks very deep and/or planted very deep, then it took a few of those young trees several weeks longer than the other trees to bud out in the spring and early summer. I feel I planted or mulched them too deep, which should be no problem going forward given that they have grown more fully closer to the surface and I will not mulch them as heavily this winter. But it did set them back unnecessarily this past year, I think. Again, cordons may turn out to be different. I may have to take that extra step of deeper burial with them, if they can be made to work at all. We'll see.

Thank you Tony.  I was wondering how this would work out, so I'm thrilled to see that you're working with this method.  Some people think you'll get way too much root mass with this method and that will drive too much vegetative shoot growth, but we'll see.  If that's the case then perhaps dense plantings can address that.  Can't wait to see what next the next years bring for you.

Subscribed!

Greg, I have seen seemingly much too much vegetative growth with correspondingly limited fruit production on many ground-dieback fig clumps but on very well cultivated, mulched, and irrigated ground that is not my own.

My red clay may be fairly nutrient rich and well draining but it does not allow for easy breathing of the roots. So I may experience that problem of excessive vegetation as the years go on but so far I've not seen more vegetative growth than I want. And once I better figure out and get the best short season cultivars in ground in quantity and perhaps figure out some limited fertilizer techniques and the like to favor fruit over vegetation, then I hope to see especially good success.

Granted, any big success of the underground cordons may result in a whole different story, as might the better growing power of older and older in-ground trees. If they begin to take off next year or in future years vegetatively but not fruitfully, well I'll have to figure out that issue as it may arise. There is so much endless clay here, and the winters are harsh enough, that I'm hard pressed to see the cultivars taking off into crazy vegetation in a way that could not be modulated and transformed into good fruit production by modest application of appropriate fertilizer and pinching/pruning techniques. At least, that's what I would try - to shift any great growing power away from vegetation and into fruit production. In ways that keep things simple, very simple, ideally. But, again, we'll see. Should be interesting, at the least.

Also, I can't imagine that others haven't experimented with this sort of thing before, underground cordoning. I would like to hear about any specific details, if so.

Hi hllyhll,
If you replace mulch with dirt (dark compost from the nurseries with no remaining wood ), and check my post on winter protections ... you'll see some resemblance ...
The difference being that I'm trying to save 50 cm of stem above dirt instead of just the buried stems .
The dark compost and dark trashcan for me should act as a heat sink and thus help keeping some more heat around the trees .
Another difference is that come spring, I remove the compost to allow the stem to breath and make its life . I don't want the stems to use energy for rooting .

As for your test, I have some remarks : Using hay and straw as you do, I would attract rodents here and they surely would kill my trees.
That same medium would probably rot and keep too much water around the buried stems and thus get the stems to rot .

Your water table must be deep sunken - here if I bury a stem it would probably stay too wet - here, at my location .

Good luck with your experimentation ! Keep us posted !
Did your groundlayers root by now ?

Most of the ground-layers seem to have long since rooted.

As for rodents, plenty of those here all around before I put any fig trees in the ground. So far: co-existence, it seems. I do have cats. I occasionally flood the fig root area. And I trample around in incidental ways keeping things somewhat disturbed, while trying not to damage roots. Also quite a number of companion plants and bushes perhaps help distract rodents. Will see if that combo is enough to keep rodents mostly at bay.

The "hay and straw" is actually lawn clippings from a neighbor in an arrangement that probably won't last as they are moving. 

Your above ground method is in a way my below ground method: earthen burial. I have far too many trees to use above ground burial effectively, and far too few trash cans, and anyway want to proceed more naturally, but great if it works for you and is your preferred method.

Yes, the water table here is nowhere to be found, basically, as I am on a steep mountainside. So, moist but not remotely too wet for stems here. Last year, as an experiment, I put a few unrooted cuttings direct into the ground. I don't think the ground warmed enough as deep as I put them. Or maybe too much clay bothered root formation. Anyway, most of the cuttings did not root, however nor did they rot over the winter and rooted instead this the following summer, surprising me when they leafed above ground, and then grew well, especially after I dug them up out of the choking clay and put them in pots with good growing medium.

I wonder if anyone has wrapped parafilm grafting tape around a few trunks or limbs in an attempt to preserve them through winter cold. Works great retaining moisture and so on in cuttings when rooting (Tim Clymer's method). I guess it would not work for wintertime preservation of wood, as the key in that far more than wind and water protection, given hardened wood, seems to be the simple need for heat, fundamentally, not falling below a certain temperature threshhold. (And regardless much wrapping can be time-consuming and costly.) Ground functions triply as heat source, heat sink, and heat insulator. Hard not to wish though that there would be some type of quick and simple, natural protection for a lot of above ground wood.

Thanks for sharing your plans +pics Tony. I have been plotting to do something very similar on a steep gravelly loam soil in zone 6a. I'm convinced there is a way to do this without great expense and large above ground work. I plan to do several trials this winter by planting 2-3 year old trees 6-12" deep, surround with rodent protection a) small rocks b) wire wrapped around trunk to 1' above ground  and backfilling with loose, breathable material such as pine needles, cones and then a few inches of the gravelly soil so that the trunks base is about 2' below surface. I'll pull it all back in spring/unwrap the wire mesh to let the soil warm and provide very low poly covered hoops for an early spring start. The poly will be taken off in in May/June after embryos form and netting will go on as needed for hail, insects and birds. I see one of the huge benefits of this kind of growing in northern areas as being able to provide the low poly hoops 2-5' wide/tall at low cost to increase yields/growing season.

I look forward to sharing more as plans become reality...

Ivan, sounds interesting. Can always learn something from various protection and micro climate type experiments.

My personal preference is to avoid wrapping and unwrapping, covering and uncovering. In this way, I try to make ripening figs as simple as possible, and as material free as possible. And my strategy to offset late arriving main crop in-ground figs is to cultivate early potted breba crops. And in this manner ripen fruit June through October. Or beyond?

So I'm always on the lookout for the earliest potted breba producing cultivars and the earliest and most robust or hardy main crop cultivars.

Tony, Interesting thread. We've gotten a few ripe main crop figs off of what I think is LSU Improved Celeste (was sold as LSU O'Rourke from Petals from the Past) about 2 weeks ago, which I considered really early. Some Florea were ripening around the same time on a tree at my Grandma's place. Both of these died back to ground level.

Just today we had our first ripe fig off of Marseilles Black VS. So Florea and Improved Celeste do seem REALLY early (as Herman's observations have shown).

Regarding your thought on wrapping the tree with something like parafilm, it might be worth an experiment. There are also spray-on antitranspirants which might do something similar, though I might be a little cautious about spraying it on a fruit tree and I'm not sure how long they last.

Tony,
Thanks for starting this topic and sharing your techniques.
The attached diagram has been modified to include the winterization plan that I'll be using this year with my in ground bushes and step over espaliers. The  scaffold branches (cordons) will be spaced approximately 2" off the ground and will be covered with Pine Shavings. This past winter all branches that were below the pine shavings survived the cold. The scaffold branches of the fig bushes will be cut back to just below the top of the mounds. Both bushes and Espaliers will be planted at ~ 3' below ground surface level.
.


Tim C,
I will be testing a white wash made from 50% latex paint on a few fig trees this season. It breathes, but could be also used as a bark "antitranspirant".

Tim, I have the same LSU Improved Celeste sold as O'Rourke from Petals from the Past. It looks like it may well be the third in-ground cultivar to ripen here (died back to ground). In future years I would not be surprised if it becomes the first to ripen, though who knows. It was among the very last to bud out here this year and yet among the first to put on fruit.

This year's main crop ripening order thus far in GROUND:

1. Mount Etna Unknown      September 1         1 yr old
   

1. Celeste PP                      September 3          2 yrs old

1. Mount Etna Unknown      August 20              1 yr old

2. Hunt                                 August 23              several yrs old

3. Marseilles Black               August 31             1 yr old

4. Improved Celeste PP      September 2          2 yrs old
   
   

If you're planting your cordons underground you might want to run some hot water pipes on either side several inches away.  If you heated up the soil in April they'd bud out in early May and you'd have a month's head start.  Of course you wouldn't want water in there over the winter.

Looks good, Pete. The diagram makes it very clear. What cultivars are you going to attach to the scaffolds?

Have you tried any of these low scaffolds in previous years? Or were your surviving branches covered in pine shavings this past winter simply low running branches that you perhaps pinned down and did not scaffold?

Very interesting that through this past harsh winter none of your branches died beneath pine shavings. How deep beneath the surface of the pine shavings did the branches sit?

Tony,
Here is a link to a thread Pete started. He has been has been evolving this process.

Japanese/Stepover Espalier Orchard the Adventure begins

I have a tree I will be putting in ground next year. I keep waffling as to whether I want to train it in the style that Pete is working with,  a very low espalier which the arms get burried in the winter. Or bush form, and trimming it down to about 2.5-3 ft each fall and burying the trimmed tree in a wire cage filled with dry shredded leaves and tarped and topped with plywood.

I like the look of the bush :) but the very low espalier would likely be easier and more effectively insulated in the long run.

The polar vortex has put many minds into overdrive on how to grow figs in cooler climates more effectively. This may have never happened otherwise.

Tony,
The plan is a work in progress, this is only my 3rd season growing figs and the 2nd season exploring the  benefits of the Japanese Pruning Technique. Most of the cultivars, some are found unknown NYC cultivars will be planted in ground and trialed as bush and espalier with the same scaffold type training, http://figs4funforum.websitetoolbox.com/post?id=6388743 . The Japanese Pruning Technique works when used in Tree, Bush or Espalier form, the key is to establish the scaffold branches and the fruiting nodes. The protection of the scaffold branches will almost guarantee a harvest. WillsC posted update pictures of his VDB espalier, http://figs4funforum.websitetoolbox.com/post/show_single_post?pid=1283967119&postcount=17 and although he's in Florida, the growth habit of the fruiting nodes has been similar in my zone.

I haven't tried winterizing the low ground hugging scaffold (cordon) as yet, it is a plan for this growing season. The 12" high cordons from last season all died this past winter due to exposure, many were 2" caliper. Yes, all the wood that was covered below the "mulch" survived and sprouted new shoots. The dieback and observations occurred in Zone 7 (NYC) and Zone 6/5B where these trees were planted. The dieback stopped at or just below the mulch line.



Calvin,
The trees that are being trained as Bush form will have their scaffold branches trained to about 2' high with the Pine Shavings mounded about 3' high. The 3' to 4' diameter mound will be enclosed by metal fencing to hold the formed shape and height.
.

Thanks for the links.

Calvin, I think the biggest beneficiaries of cold weather fig growth improvements could be those in zone 5 and colder, though those in zones 6 and 7 and so on would benefit greatly too. Whether to bush or to cordon, why not try both together, with a low cordon shooting out to one side of a bush? Either could be dispatched later, or both maintained, I would think.

Pete, If I were to try ground hugging cordons (2-3 inches above soil surface), which I may need to especially if the underground rooting cordon idea doesn't work, then I would think of preparing ground hugging cordons for winter as a form of burial as opposed to covering. What this means in practice, I don't know. Using dirt instead of wood chips? Or running the cordons in swales that don't retain water, either because they are well draining or do not run on contour? then covering with dirt or mulch in late fall and sweeping it out in early spring?

My underground cordons I would expect sooner rather than later to become essentially elongated bushes, with all the problems and possibilities that that might entail.

Tony,
In answer to your questions, Yes, but wood shavings are much easier and quicker to move than soil or sand.

I am going to try the step-over-espalier form for growing some plants in Kentucky.  A few comments about the burried cordons.  It would seem to a method for protecting more roots of the same plant.  However it not particularly different from planting rooted cuttings closely and expecting to have all plants rejuvinate from roots after being frozen back to ground.  The practical results will be the same as thinning the resulting bush, multistemmed growth, that follows dying back to ground. 

I'm just a beginner at figs, but it seems to me that the key to getting early shoot development and growth is either warmer ground or warmer stems/branches, or possibly both.  The deeper the soil cover the later the roots warmup.  While that soil cover provides temperature stability to survive the winter, it is going to be slow to warm and trigger growth.

My plan it to try to use two foot tall styrofoam sheets to create an above ground box, open to the soil.  Fill the box with dry leaves which will further insulate the cordons.  The heat resevoir of the soil should keep it from having the hard freeze and the box shields from winds, without being some large teepee arrangement.  Last winter the lows were about -6 F but the soil temperature at 4" depth did not get below 32 F.  I expect the section I'm going to cover and protect from surface air exposure to stay above that temperature.  The leaves can be pretty easily placed or removed with a leaf vac blower.  I hope to have some living above ground growth in the cordons to help trigger plant growth in the spring and be able to get pretty fast soil warmup when the insulation is removed. 

I have such limited space with adequate sunlight that I plan on only letting each plant and cordon be about three feet horizontal as a way to have more varieties.  That should also lead to smaller extent of root growth on the surface plane.  In any case it will probably require quite a lot of pruning and pinching to limit plant growth to only three or four verticals and no additional shoots from the ground.

My understanding is you need a nice wall or fence to benefit fully from the espalier form?

With no wall or fence is there any reason why I can't use the espalier form and have 4/5 cordons spread out evenly in all directions?  
The cordons would be trained as explained by Pete.  Still close to the ground so easy to apply winter protection.