Yes, know it's not a fruit or veg but my rather fine red acer is very potbound and I need to transfer it to a bigger pot, so advice please!
I can get it out of the pot (I hope) because the top is wider than the base but the roots are thick and tangled. Should I wait until all the leaves have fallen off, and then carve off some of the roots (like like one does with a bonsai)(and if so, what proportion?) and then backfill fresh potting compost around the edges in a bigger container? I don't usual fail with transplanting but am a bit nervous about this one as I don't want to kill it.
Transplanting a potted acer
Moderators: KG Steve, Chantal, Tigger, peter, Chief Spud
Don't worry Primrose - I've done this loads & you shouldn't lose the tree if you are careful.
Wait until the leaves have dropped and the tree is completely dormant - about end October or start of November. Water it really well and the root ball will come out more easily and hang together. You can root prune - just cut the really thick roots looping round the outside, but don't pull the rootball apart totally. Aim for 25% reduction max. This will stimulate the growth of finer feeding roots.
Repot into a slightly larger pot with John Innes No 2 (not peat based compost) and don't put any fertiliser in. Next year the tree should grow like crazy and you can start feeding the spring after that.
Sue
Wait until the leaves have dropped and the tree is completely dormant - about end October or start of November. Water it really well and the root ball will come out more easily and hang together. You can root prune - just cut the really thick roots looping round the outside, but don't pull the rootball apart totally. Aim for 25% reduction max. This will stimulate the growth of finer feeding roots.
Repot into a slightly larger pot with John Innes No 2 (not peat based compost) and don't put any fertiliser in. Next year the tree should grow like crazy and you can start feeding the spring after that.
Sue
Oh Jopsy - I never meant to insinuate anything of the sort 
Most failures are because people pot acers up into much bigger pots of general multi-purpose. They hate being in really wet soggy compost, especially over the winter.
I only know because winter time is when you pot on all your old stock and with my vast (3 years ) of experience in the industry I've potted on a ton of trees and shrubs - least that's what it feels like by the end of potting season 
Sue
Most failures are because people pot acers up into much bigger pots of general multi-purpose. They hate being in really wet soggy compost, especially over the winter.
I only know because winter time is when you pot on all your old stock and with my vast (3 years
) of experience in the industry I've potted on a ton of trees and shrubs - least that's what it feels like by the end of potting season
Sue
