Wow, what a find! Well, I wish you'd said just how large an opening there is in the rock for roots to find their way through to the soil underneath, because that can make a difference to the tree's future, but as there is obviously something there, what I would do is get a large training box (a wooden box with widely open slatted sides, screened, with a solid bottom) and use a peat-free very gritty mix. Keep it in filtered sun or light shade for at least a month or so, and well watered. Trim the green branches to a couple of leaf pairs each, and add a little moss/compost to the area where the trunk comes out of the rock, scoring the trunk there to encourage new roots to grow and spread on the rock and not just inside. In March of next spring you can lop off branches and you'll have a better idea of what to do all around by then. Go to www.bonsai4me.com for lots of good info., and read everything you can on bonsai. Best idea of all - find a club in your area, because that's where to see how things are done, and ask lots of questions of people growing in your environment. Please keep us posted on how the tree goes!

Thanks Lucy! I went to the site. As you say there is a lot of good information there as well as great pictures.

I guess didn't say that I wanted to leave the stone with the nadina in the gravel area year round. It would have been nice if a knarled youpon holly which I have growing nearby would have voluntered to grow in the rock. Nandina isn't exactly a plant that lends itself well to becoming a terrific bonsai plant. But since it is there I will work with it.

Anyway, this being a bonsai site naturally one would be thinking of a good container and soil so I appreciate the information. I will add the moss and compost around the trunk; there is a little depression there that will hold it (the hole is very small by the way) and the stone now being in a little more sun will grow some of that nice lichen that I have seen on other rocks. Also I think the roots will find their way into the soil beneath the gravel, but I don't want it to get too big. Mainly I just want to enhance the look of the ordinary nandina. It was suggested by someone to take off every other layer of leaves to give it more of a graceful bamboo effect. What do you think?

Thanks again for looking and for your reply!