If there is anything but a smidgen of lime in there (can you look up white coral for more info?) you could have trouble, as well as having a bunch of it if at any time you choose to try and do anything with the roots, which will be positively glued/fused/welded to the coral forever.

I tried that and got coral make up for women?
I'll try re-wording my search.
If any one knows the make up of white coral please jump in.
Paul

"Lime" is just a loose term for various naturally occurring materials, as well as their derivatives, and is too general to be of significance to what you're asking. Coral is primarily CaCO3 (calcium carbonate), and while it may not be so large a problem in the well-aerated soils as we are wont to use in bonsai, it does combine with soil CO2 to form (Ca(HCO3)2) (calcium bicarbonate), which is reported to have toxic effects on roots - not so much because the solution is phytotoxic, but because of the fact that it interferes with uptake of other essential elemental nutrients, and its accompanying tendency to cause an upward creep in media solution pH.

That said, I have some landscape plantings that use rock very rich in CaCO3 (fizzes when you put vinegar on it). They are many years old and are showing no ill effects. If you like the looks of the coral, why not try it with a pine seedling and/or a maple volunteer?

Al

Tapla, your knowledge is infinite!

It just so happens that I just potted 2 "small leaf" maple volunteers from a "large leaf" maple tree. (Not sure of the species but it looks like a maple syrup tree) I'll try it on one of them.
Paul