New to Bonsai Grafting Question

[TheBlackBonsai]

I’ve acquired a few Red Japanese Maples (fire glow, red emperors, bloodgood) that have been grafted into a green Japanese Maple root stock, and my question is what the heck happens to the green root stock after it’s fused to the red maple? Is it now a red maple? Are they green maples? Can I grow them out for bonsai or better off for propagation? Any input is greatly appreciated. Thank you!
- Jaz

 

[Dav4]

The green palmatum root stock maintain their original genetic complement and the red grafted portion retains it's own. If you were to cut away the red grafted portion and the root stock had some latent buds that started to grow, the leaves would be green. In bonsai culture, visible graft unions are frowned upon, but well done ones can sometimes be used. I personally wouldn't work with grafted maples if I had the choice.

 

[Shibui]

The top section of a grafted tree is the named variety. Everything that grows above the graft will be that variety. Below the graft, including the roots is the green seedling maple which is there because the roots are strong and will help your maple grow. well.
If shoots sprout form below the graft those shoots will be green maple which means the green maple is still there but does not usually grow. Any shoots from the roots stock will usually grow faster than the top so if they do sprout and you allow them to grow eventually they will outgrow and maybe even kill the grafted top.
For all intents and purposes these trees are the red maple variety you paid for.

For bonsai purposes grafted trees can have problems:
The graft union may cause an unwanted kink in the trunk which does not look good. Usually small bends will disappear as the trunk thickens.
There may be an obvious change of bark texture or color above and below the graft union which does not look good. On the other hand most JM bark is similar so if that's the case no problem.
Graft union sometimes swells which also looks bad for bonsai. If there's no sign of different size above and below no problem.
Sometimes either the stock below or the scion above grows more which is also ugly.

For those reasons grafted trees are often shunned by bonsai growers however not all grafted trees are bad. There are many great bonsai grown from grafted trees.

It is usually possible to layer the top section so the green maple stock and the graft is gone. Whether that is worth the time and effort depends on how nervous you are about the possible outcomes and what the grafts look like.
You can also use these trees as stock plants for cuttings or layers if you are able to manage either or both.

 

[TheBlackBonsai]

Thank you for clarifying this for me, wow. That is very interesting to learn and a little sad because I thought I had a nice little stash of red maples. The grafting site is very swollen on all of the seedlings and you can clearly see where the two plants are trying to become one. There are red maple shoots sprouting from the top and green shoots sprouting from the lower root stock on most of the seedlings which sparked my questions. Back to the drawing board. The trails of a noob I guess

Above everything I greatly appreciate your wealth of knowledge and the time it takes to explain these concepts.
Thank you kindly!
-Jaz

 

[sorce]

Welcome to Crazy!

Sorce

 

[TheBlackBonsai]

Welcome to Crazy!

Sorce

Seriously!

 

[penumbra]

Graft union sometimes swells which also looks bad for bonsai. If there's no sign of different size above and below no problem.
Sometimes either the stock below or the scion above grows more which is also ugly.

This is a real problem that may become much more pronounced as years go by. When you have a 30 year old plant with an overgrown rootstock, well..... there's no cure for that.