Temporary Grafts to Accelerate Growth in Dwarf Varieties

[DaveG]

I've had the idea knocking around in my head for a while that it might be possible to accelerate trunk, branch, and root thickening of dwarf varieties of some trees by grafting normal stock to the ends of branches and roots. It may depend on the specific cause of dwarfism in the tree in question, of course. I've spent some time looking for information on this idea and that's turned up nothing so far. I was wondering if anyone here has tried this or something similar.

The basic idea is to let our dwarf tree grow for a few years at its normal rate, which yes, can be painfully slow, then graft a non-dwarf scion to the tip of whatever we desire to thicken up. The graft should be strategically placed beyond the intended point of a chop that's to be performed in the future, so that the non-dwarf part is later removed, leaving us with a nice thick trunk on a very slow-growing tree with short internode spacing. This could be done progressively higher so as to obtain a nice taper and then finally stopped when our tree has the intended trunk shape and thickness.

Also, I see no reason to remove the tree's other dwarf branches as we go, as they will still provide the tree with energy, help it thicken, and can possibly be prepared for further grafts higher up. Depending on how the tree distributes growth while it's grafted, it seems like it would even be possible to start shaping lower branches before all of the grafts are removed.

I believe, using this technique, it might even be possible to take some dwarf varieties to a "terminal size", where they effectively just don't want to grow vertically anymore once the non-dwarf tissue is removed, effectively taking on some growth characteristics of very tall specimens of non-dwarf varieties. But it will take years to determine if this is the case.

I'm presently preparing to try this on a 5-year-old dwarf trident maple I currently own, which I purchased as a "Miyasama Yatsubusa", but I believe should correctly be called "Miyasama Kaede Yatsubusa". I have some trident maple seeds in the fridge that I'm preparing to try to approach graft to the branches of it as soon as the seedlings are old enough. I also want to try it with several varieties of Chinese elm (Hokkaido, Cantlin, Cantlin Contorted), but I currently lack the dwarf specimens I intend to try it with and probably won't have them for at least a few more months.

 

[Juniperus Californica]

Hey DaveG,

Why wouldn't you take a large trunk and graft the dwarf variety onto it. That way you get the best of both worlds - large trunk and dwarf foliage. Sounds to me like you're going about this bassackwards.

JC

 

[Bill S]

Hey DaveG,

Why wouldn't you take a large trunk and graft the dwarf variety onto it. That way you get the best of both worlds - large trunk and dwarf foliage. Sounds to me like you're going about this bassackwards.

JC

Poifect way to look at it JC, good catch.

 

[cbobgo]

Brent has a tree like this, but it happened naturally, not with grafting. One of his small Kingsville boxwoods had a branch that reverted back to regular boxwood with larger leaves and stronger growth. Rather than cutting it off, he let it grow as a sacrifice branch and it has significantly thickened the trunk of the tree.

So Dave, I think your concept can work.

- bob

 

[DaveG]

Juniperus Californica,

As I understand it, there are many possible causes to dwarfism. But a common cause is that there's a genetic condition in the tree that causes root and branch tips not to respond in the normal way to growth regulators. If this is the cause of dwarfism in the specimen in question, grafting non-dwarf stock to the tree should temporarily make the tree non-dwarf, as far as those branches and roots are concerned. Effectively, such a tree should grow (and thicken) as fast as any other specimen of the same species until the graft is removed. Grafting a dwarf top to a large normal trunk would initially result in fast growth in the dwarf top, but this may also subside once the excess energy in the roots is used up. And from that point forward, growth may continue as if the tree is simply a dwarf, again, depending on the cause of dwarfism.

But I have some other very good reasons not to graft a dwarf variety onto a large trunk.

First off, I don't want any graft unions visible on the finished tree. From my experience, they're usually at least a little ugly. The best scenario I can think of is that the graft union would be below the soil line, but then no good nebari could be produced. A more desirable nebari could be produced later through air layering the top back off the non-dwarf trunk, but that leaves us starting over with small roots on the nebari. This is also undesirable, of course, if it can be avoided.

Second, I don't personally have a large trunk of trident maple, chinese elm, or anything else compatible to graft these dwarfs to. I had considered growing non-dwarf trees in their own pots, then making a graft between a branch and the end of a root of the dwarf, then chopping the rest of the top of the larger tree so it sends all its energy for new growth to the dwarf specimen. In my case, that would mean either buying a large and having it shipped just to chop it down or growing it for several years just to do this. (I haven't seen either for sale locally. Most of our local nurseries here kind of suck and these varieties aren't very common in the area anyway. But no matter how I do it, this would probably be an expensive technique.) What I decided was that it is simpler just to graft the non-dwarf tissue to the tree to begin with and let it grow.

An added benefit is that a dozen of these grafts could be performed on a tree at the same time, which would be difficult in grafting to larger specimens. You might ask, "why would I want to do a dozen of these grafts at the same time?" The reason is simple. On my maple, I've selected four branches for this and I selected and marked six radial roots last time I repotted. The branches all originate from about 2" up on the trunk. I figure I can graft all four branches for now, let them thicken nicely, then remove two of them later, which will give me a thick lower trunk that branches off two ways, with the added bonus of an acceptable amount of taper in this 6" span of the trunk. It's what I'm hoping for, anyway.

 

[DaveG]

Brent has a tree like this, but it happened naturally, not with grafting. One of his small Kingsville boxwoods had a branch that reverted back to regular boxwood with larger leaves and stronger growth. Rather than cutting it off, he let it grow as a sacrifice branch and it has significantly thickened the trunk of the tree.

So Dave, I think your concept can work.

- bob

I actually find it really interesting that would happen randomly. It seems like the chances of that would usually be astronomically slim, but that may not be the case with all dwarf varieties. If I had a tree this happened to naturally, I'd be tempted to keep part of that on it permanently.

 

[rockm]

"It seems like the chances of that would usually be astronomically slim, but that may not be the case with all dwarf varieties. If I had a tree this happened to naturally, I'd be tempted to keep part of that on it permanently."

Not at all. It happens pretty frequently and naturally. Spontaneous mutation in plants has produced literally hundreds of thousands of different cultivars, including dwarf plants:
http://aggie-horticulture.tamu.edu/tisscult/Chimeras/chimeralec/chimeras.html

What you're proposing doesn't make that much sense to me and is ultimately a waste of time. Simply put the dwarves in the ground and wait, or get a bigger supply of dwarf stock. Your way is labor intensive and would require about the same time to develop as a regular dwarf plant in the same situation...

 

[DaveG]

"It seems like the chances of that would usually be astronomically slim, but that may not be the case with all dwarf varieties. If I had a tree this happened to naturally, I'd be tempted to keep part of that on it permanently."

Not at all. It happens pretty frequently and naturally. Spontaneous mutation in plants has produced literally hundreds of thousands of different cultivars, including dwarf plants:
http://aggie-horticulture.tamu.edu/tisscult/Chimeras/chimeralec/chimeras.html

What you're proposing doesn't make that much sense to me and is ultimately a waste of time. Simply put the dwarves in the ground and wait, or get a bigger supply of dwarf stock. Your way is labor intensive and would require about the same time to develop as a regular dwarf plant in the same situation...

I'm fully aware of the causes of such things. The article you linked is one I wasn't aware of though and it is interesting.

But when I was talking about the chances being so slim, I was referring to the specific chances of a twig on a dwarf variety reverting back to not being dwarf anymore. It's reasonable to assume that, often, the cause of dwarfism in a witch's broom is due to a single mutation which changes a normal gene from that part of the plant. (As I understand it, the case with my maple is that the specific condition is supposed to be heritable, but recessive, implying a damaged gene related to growth regulation.) For this to be reversed in a forming bud, a random mutation would have to occur that somehow corrects the previous cause of dwarfism. In most cases, there are probably only a few possible point mutations that could accomplish this.

In cases where the original dwarfing mutation creates a gene that causes manufacture of proteins that inhibit growth, it would be far more likely the mutation would be reversed randomly, as a mutation that reverses the dwarfism would only have to corrupt that gene, simply making it not work anymore. I'd guess this is the case for the Kingsville Boxwood mentioned previously.

As for your second point, if I were to put the dwarf in the ground and wait, it would still take a very long time to get it up to size, simply because it's a dwarf. If I put my maple in the ground for 30 years, it might get 6' tall with a trunk between 2" and 3" thick. (At 5 years, it's 9" tall with a 1/2" trunk.) But then I'd have waited until age 60 for this, just to do the first trunk chop. I'd prefer to spread 10 or 15 hours of work over a period of maybe 5 years to get it to that same size. I understand that the art of bonsai requires patience, but I'd prefer to finish some of my trees while I'm still alive, instead of letting my descendants finish them 50 years after I've died of old age. Maybe I'll even get to enjoy some of them* for a decade or so before I pass on.

And buying large enough stock simply isn't an option for me right now for what I want to do. I'm not flush with cash, ready to buy a nearly completed tree. Even if I did have the money, I'd rather be involved in the tree's first few serious prunings and its early shaping. I might be able to buy a field grown tree, but it likely wouldn't have the start of the kind of nebari I want. I strapped my maple to the top of a flat rock, but it barely needed it. Nearly all of its natural root development was horizontal. After slanting it at about 20 degrees, it has well-developed roots almost all the way around, within 1/4" of soil level. All I really need to do with it now is keep making those roots bigger, which I hope to do with the temporary grafting.

*Aside from the enjoyment of working with them at this stage, which is also rewarding.

 

[Juniperus Californica]

...What you're proposing doesn't make that much sense to me and is ultimately a waste of time. Simply put the dwarves in the ground and wait, or get a bigger supply of dwarf stock. Your way is labor intensive and would require about the same time to develop as a regular dwarf plant in the same situation...

I agree with rockm! Well, I've learned more about dwarfism than I think I"ll ever need and DaveG if you're asking my opinion, from a bonsai stand point, don't get so defensive - lighten up, we're trying to help. Maybe you'll pioneer some new technique and if you do I'll be the first to congratulate you. However, in the mean time, ask yourself how do your bonsai look? Is the time you're spending advancing your collection? Are you learning the basics first before taking off on some wild goose chase?

Anyway, have fun!
JC

 

[DaveG]

JC, while I may seem, in a negative way, quite defensive, it may not be so negative as it comes off. Today is a really good day for me, for reasons that have nothing to do with my trees (though it will mean as a result my wife won't get mad if I get a few more), and it would be hard to change that. Simply put, I'm in a good mood. And I like to talk about this stuff. So that's what I'm doing.

That said, I started this thread and I'll defend my ideas in it. And if I had been offended by what I suggested being called "bassackwards" without a particularly good reason, I don't think I would have been out of line. But believe it or not, I was defending my ideas very calmly and I was enjoying the discussion. If nobody tried my ideas about technique I'd be quite fine with it. Honestly, when I thought of the idea, I considered just never telling anyone how I did it if I manage to make some really awesome dwarf tree this way. I hope sharing of ideas about technique is the more welcome thing to do here.

As I am in an apartment though, and will be for several more years, I really do only have 3 trees right now that I consider candidates for becoming bonsai and I enjoy working with them. I have no trees I consider trained. I'm of the school of thought that a tree doesn't suddenly become bonsai if you put a twist in the trunk of it or trim it a little. (Though, I've seen the odd exception that can be made to look pretty good fairly quickly.) I expect it'll be a while before I have anything I consider good. And I think it will be a good while before I consider myself good at bonsai.

 

[Vance Wood]

I think what will happen is that the scion will develop at a faster rate than the stock (the dwarf) you want to develop which will leave you with a reverse taper and an ugly scar to have to deal with.

 

[DaveG]

I think what will happen is that the scion will develop at a faster rate than the stock (the dwarf) you want to develop which will leave you with a reverse taper and an ugly scar to have to deal with.

I've already considered that possibility, which is why when I do this I'm going to leave at least an extra inch or so below the graft union that I can cut off later without it being a problem. I'm also considering the possibility that the difference in growth rates might be so severe that the graft will simply fail after a few years. I think the outcome would vary a lot depending on what two things are being grafted and why the dwarf plant is a dwarf to begin with.

 

[Smoke]

I've already considered that possibility, which is why when I do this I'm going to leave at least an extra inch or so below the graft union that I can cut off later without it being a problem. I'm also considering the possibility that the difference in growth rates might be so severe that the graft will simply fail after a few years. I think the outcome would vary a lot depending on what two things are being grafted and why the dwarf plant is a dwarf to begin with.

Rather than spend a bunch of time defending a process you seem pretty sure you are going to do, just do it and report back in two or three years with the results. Then when you have something that really proves your point there is no reason to bantor and defend your position, you will have the proof.

I have three or 4 projects going on right now that would cause a real stink here but I'm not showing anything till I know it works. I already argue enough.

Al
http://bonsainut.com/forums/showthread.php?t=3149&highlight=trident+maple

 

[Smoke]

I've had the idea knocking around in my head for a while that it might be possible to accelerate trunk, branch, and root thickening of dwarf varieties of some trees by grafting normal stock to the ends of branches and roots. It may depend on the specific cause of dwarfism in the tree in question, of course. I've spent some time looking for information on this idea and that's turned up nothing so far. I was wondering if anyone here has tried this or something similar.

The basic idea is to let our dwarf tree grow for a few years at its normal rate, which yes, can be painfully slow, then graft a non-dwarf scion to the tip of whatever we desire to thicken up. The graft should be strategically placed beyond the intended point of a chop that's to be performed in the future, so that the non-dwarf part is later removed, leaving us with a nice thick trunk on a very slow-growing tree with short internode spacing. This could be done progressively higher so as to obtain a nice taper and then finally stopped when our tree has the intended trunk shape and thickness.

Also, I see no reason to remove the tree's other dwarf branches as we go, as they will still provide the tree with energy, help it thicken, and can possibly be prepared for further grafts higher up. Depending on how the tree distributes growth while it's grafted, it seems like it would even be possible to start shaping lower branches before all of the grafts are removed.

I believe, using this technique, it might even be possible to take some dwarf varieties to a "terminal size", where they effectively just don't want to grow vertically anymore once the non-dwarf tissue is removed, effectively taking on some growth characteristics of very tall specimens of non-dwarf varieties. But it will take years to determine if this is the case.

I'm presently preparing to try this on a 5-year-old dwarf trident maple I currently own, which I purchased as a "Miyasama Yatsubusa", but I believe should correctly be called "Miyasama Kaede Yatsubusa". I have some trident maple seeds in the fridge that I'm preparing to try to approach graft to the branches of it as soon as the seedlings are old enough. I also want to try it with several varieties of Chinese elm (Hokkaido, Cantlin, Cantlin Contorted), but I currently lack the dwarf specimens I intend to try it with and probably won't have them for at least a few more months.

I can tell you from experience that catlins and hokkaidos won't grow faster with Chinese elm tips. You have to put the better variety on the root stock if you want accelerated growth. Unless you are dealing with Chinese elm, most other cultivars are mutations anyway. I have all three, contorted, catlin and hokkaido and all three are painfully slow.

As far as trident maples, I see no real advantage in dwarf varieties that grow slower over the regular cultivar. With nearly 85 tridents in my backyard I can tell you that leaf size can be as small as a little finger when cultivated properly.

 

[DaveG]

Rather than spend a bunch of time defending a process you seem pretty sure you are going to do, just do it and report back in two or three years with the results. Then when you have something that really proves your point there is no reason to bantor and defend your position, you will have the proof.

I have three or 4 projects going on right now that would cause a real stink here but I'm not showing anything till I know it works. I already argue enough.

Al
http://bonsainut.com/forums/showthread.php?t=3149&highlight=trident+maple

I can tell you from experience that catlins and hokkaidos won't grow faster with Chinese elm tips. You have to put the better variety on the root stock if you want accelerated growth. Unless you are dealing with Chinese elm, most other cultivars are mutations anyway. I have all three, contorted, catlin and hokkaido and all three are painfully slow.

As far as trident maples, I see no real advantage in dwarf varieties that grow slower over the regular cultivar. With nearly 85 tridents in my backyard I can tell you that leaf size can be as small as a little finger when cultivated properly.

I can tell you a very good reason why I should come here with it now. An experiment like this, for me, is also an experiment in growing trees I'm unfamiliar with up to this point. Some of these trees, as I understand it, are trees that some people find difficult to grow. That doesn't make for a very scientific experiment. I've looked for information about Hokkaido and Cantlin, but the most promising piece of information I had found (regarding this idea) so far was Brent's information on Cantlin Contorted, where he talks about how it tends to grow its roots.

http://www.evergreengardenworks.com/cocatlincare.htm

This agrees with what you're saying, of course. But you're saying it about two others cultivars. The most important thing it tells me is that all of these elms are dwarfs because they choose a very imbalanced ratio of root to shoot development, which I suspected, but didn't really know for sure. With trees that behave this way, I think I'd choose a slight variation on what I described before.

I would probably start by trying to develop some radial roots on the tree, perhaps by planting it over something flat to force them to develop horizontally. (Or I could simply find a specimen with enough radial roots to begin with, which is probably what I'll try to do.) Then I'd graft some normal roots about 4" out. After the grafts have taken, I'd gradually lower the soil level until none of the original roots are touching soil. This should effectively undwarf the tree without completely removing the original nebari. When the fast growth work is finally finished, the soil level could be raised to again cover the original roots, which should quickly take over once again. The grafted roots could be cut off one at a time to encourage the process.

I'd also like to point out that this information about the behavior of their roots would seem to imply that if one grafted Hokkaido/Cantlin/Cantlin Contorted roots a little below the soil level on a fast growing variety of Chinese elm, those roots should steal enough energy from the top that they could effectively dwarf the tree. They would probably also thicken any root(s) they're feeding from. I'm tempted to try that at some point as well.

With my trident maple, and yes, I do hope to keep full-sized and other cultivars eventually, I think the best reasons for keeping it an all dwarf tree at the end of the process are its shorter internodes (which really aren't that short sometimes, so I can imagine how the full-sized trees are), its slightly different leaf shape, and, of course, the fact that it isn't going to try so hard once it's "done" to become a 30' tree. Not that any of this prevents any other kind of trident from becoming good bonsai. I just feel the need to try this on this one.

The leaf size on mine seems to top out at about 1" though, which would seem to be a good deal smaller than the standard. Typical early spring growth is also often smaller than what you describe, even by the fall. (See attached.) I just don't pinch the tree back to keep the leaves so small, because more ramification is simply not an important objective to me right now. Time will tell if I can produce leaves even smaller than this on a regular basis once the tree is ready for it.