I have tried a couple times without success of starting a new plant from a segment of root.  When my potted plants expanded their roots into the ground I simply tried to snip if out with a couple inches above ground. As well as figs come back when everything above ground freezes I thought this would be workable, however I was not successful. Moving my plants in prep for colder weather and several have expanded from their pots. I know that means it's probably time to move them up a pot size, but I will undertake that in spring. Any advice appreciated.

Thanks

From what I have read here, it is not possible to start a tree from root cuttings.  You must have some "trunk" material available in order to grow more trunk.  I never investigated the science behind it - this may be a question for Al (tapla)

I wonder if you tried to graft a bud onto a section of root if it would take. Anyone tried this yet? I was thinking this might work with a root that has grown out of the pot and into the ground. A T bud or saddle graft might work.

I agree with Jason.

Have you ever tried to graft onto the roots?

No I never did, and do not intend to.

Thanks Folks. On grafting as George notes I don't know if there is a cambium on a fig root, and maybe will not generate a leaf bud either and that’s  why I have never seen a plant develop. I have grafted a few other genus but not figs, but maybe I will try on a cultivar that is noted as non vigorous .  I want a plant to be able to come back true to cultivar after a freeze, but I do try a graft I will probably have to try on above ground wood as I can’t see try to align cambium on the fig root I just looked at. I assume  some part of a trunk must remain on the trees that come back from freezing to ground. Just glad It’s just not me on them developing solely from root wood.

it would lead one to wonder, though....

if cambium in a root is required to make a shoot, and there is no cambium in a root, then how does a tree create suckers from underground roots?

some food for thought.

I have roots from a tree that got rooted into the ground from a pot 3-4 years ago. They are still alive and have never produced a shoot or leaf.

If I had to take a guess, I would say anyone who has "rooted" a piece of root probably had some portion of the trunk, or vegetative cells still on the end of the root where it was attached to the tree.

@satellitehead

I think that in most cases, keeping the root cutting viable long enough for tissues in the vascular cambium to dedifferentiate (from adventitious root initials [note that when referring to root initials, most of those using the term are actually describing root primordia. Initials can't be seen w/o removing the periderm/bark. Primordia can.] and then redifferentiate into adventitious shoots is probably the limiting factor. I think that in most cases too, timing is involved as a primary consideration and is closely tied to the length of time it takes for shoots to form. If you take root cuttings early in the spring, before onset of the spring flush is signaled by bud movement, you'll have best luck because the root will have an ample store of carbohydrates to drive propagating success. The worst time to try to propagate by root cuttings would be after the spring flush through mid-July. You could also take root cuttings and hold them over winter in a damp medium with the distal end of the cutting at or just below the soil surface.

I've rooted several species of tropical ficus from root cuttings, and had mulberry (a very close relative of Ficus - same family - Moraceae) sprout from roots left sticking out of the ground after removing the tree (for bonsai).

Very recently, I related a story about my repotting a large Ficus specimen bonsai in June of '10. A large root I'd removed lay in the sun for a couple of hours before I got the idea it would make a good bonsai start for a friend somewhere. I potted up the root cutting, over-wintered it under lights, nicked the bark several times to confirm it was indeed still viable, and continued to wait. It wasn't until June of '11 that it started to form buds in the callus around the distal wound site. It's growing well today, but it took a whole year to get anything going.

Just to make sure I was on solid footing, I checked a university level text on propagation (Hartmann & Kester's Plant Propagation - Practices & Principles) to be sure that carica was indeed on the list of plants easy to clone via root cuttings, and it was. I also did a quick search of the net & found this page you might find interesting. It too, lists carica as an easy species to clone via root cuttings: http://www.weekendgardener.net/plant-propagation/rootcuttings-120812.htm 

I hope that helps.

Al  

So a surface root, one that has already begun the process of forming vegative buds because of exposure to air and sunlight, should be the fastest and most successful, correct?

A branch can form roots and a root can form branches. Makes sense to me.

Well then ...