Blackberry question

We have a thornless blackberry which was developed by my wife's grandfather many years ago. It did very well in our last place but has really struggled here - volcanic rock underneath with extremely poor drainage, heavy clay in most places, etc. I'm wondering if the blackberry might do better planted in a half oak wine barrel? Any advice very welcome

Could you not make a deep raised bed just big enough for the plant? It would root in the bed and eventually send roots further out even if the soil below wasn't perfect.
IMO In a container, albeit a large one, the roots would be restricted and the plant end up pot bound in the long term.

Now there's a good thought and shouldn't be a problem to make with all the pallets we have lying around here. Thanks for that