Like all members of the Prunus family (even the ornamental ones) it is probably, nowadays, grown on a root stock and it is that which will determine the ultimate size of the tree. So it is a bit difficult to 'fight against nature' if it is grown on a vigorous root. If you are sure it is not already on a dwarfing stock (check with where you bought it) then the only thing I can think of is to effectively 'bonsai' it. It would mean buying something like a half barrel and growing it in that. The only problem you have got then is if you want it in the ground. In that case you could get something like the barrier that is sold to restrict bamboos, which spread by runners. As long as it will not rot (which is why it is difficult to sink a barrel in wet soil) then, as long as you can restrict the roots, it should dampen its growing ability. Not guaranteed to work I am afraid but unless somebody else can suggest an alternative, then I can't do better.

I have this tree and after 15 years it is about 15 feet high. It is on a clay soil and not restricted in any way. It can be pruned, but only in summer or you risk silver leaf disease. And anyway it just grows more! The bark is amazing though, everyone comments on it.

Thanks for your advice. I bought it for the beautiful bark Volunteer. Regards