Too late to repot an Acer [UK]?

Hi all!
A year ago I wrapped an Acer palmatum around a small rock and buried it in sharp sand. I thought I'd killed it until last week when I saw buds and now the leaves have just sprouted. I'd like to check if the root-over-rock has worked but is it too late into Spring to take it out? The tree is about 3 or 4 years old but quite skinny in the trunk (1 cm in diameter?). We've just had a week of really hot weather which is unusual - don't know if that info is of any use..?
Thank you!

Be patient.
Wait another year to let the tree atatch to the rock.

Thank you Peter. And is it OK to leave it in the sand? It doesn't need to go into soil now?

hi,
sand isnt the best growing medium for an acer - stays wet, then very quickly goes bone dry. To develop the size (both to trunk and roots) you need to feed heavily and get some extension growth so a better potting soil will help you achieve far more than waiting another year. 3 to 4 years proper growth should have given you 3-4cm of girth to the trunk on a normal palmatum

Also you are not actually repotting in the traditional bonsai sense where roots are pruned back by up to 2/3rds - all you are doing is moving a tree from one container and potting medium to another and this is fine to do at any time. In the middle of last summer I 'repotted' my large red maple in full leaf from a very small shallow pot to a larger pot as it was drying out too quickly. The roots were combed out etc and some ends snap off but the tree was fine and then spent the rest of the season improving. Just be gentle, brush off most of the sand and surround the entire rock / rootball in better soil. Give it 2 weeks to settle and feed for the rest of tthe year.

we've always done 'soft repotting' ie no hard root pruning on young trees through-out the year at the local bonsai nursery on all maples, elms, junipers etc and they are all perfectly fine. I think the 'bud burst' advice is perfect for everyone to stand a high chance of success with all repotting, but with good care and aftercare many repotting jobs can be done at any time - just not the hard pruning of all root tips when in full leaf

cheers Marcus

oh - and Cardiff will be down to about 5 or 6 degrees next week so the tree will go dormant again - if you do the work this weekend just protect from cold winds and dont overwater - if the coming cold weather hangs on a few weeks wait until you see active growth before feeding.

marcus

Marcus, thank you - that's really great information for a noob like me! I appreciate you taking the time.