What size pot?

[beguilingeyes]

This may be a 'how long is a piece of string' question, but we have a dwarf cherry tree and I wondered what size pot we should put it in?

What's the actual height of the tree at the moment?

Is it in a pot now? If so, you shouldn't re-pot it into anything massively bigger than what it's in - you go up by a couple of litres or a few inches, gradually. If you re-pot a tree with a nice well-developed root system into a much larger pot full of soft compost (or even compost and top soil), the risk is that the compost around the roots just becomes sodden in wet weather (as it has no roots to wick away the water). This can mean the roots of your tree end up rotting. So, even if you ultimately plan to have a tree growing in a huge half-barrel pot, if it's currently in a tiny 2ltr pot, you need to size up in increments as it grows.

Is this a cherry you'll be keeping in a pot permanently? If so you may end up needing a really huge pot. But it'd have to be quite a tiny cherry to be happy long term in a pot - what is it?

It's in a smallish pot at the moment. We just bought it from a garden centre.
It's a Celeste Gisela (5?).

Gisela 5 is the rootstock. That means it won't grow very tall - about 10 feet after 5 years. You can get away with keeping this in a container throughout its life, but you need to increase the size gradually, and once it is in its final container (I think probably a 50ltr pot ideally; a large half-barrel could be nice), you will need to feed it carefully. At the moment, you want to stake it and/or put it against a nice sheltering wall - it won't be very stable as the Gisela rootstock will mean it has rather shallow roots.

It will be a lovely tree - nice choice!