Japanese maple

[SteveD]

We have a Japanese maple (now about 100 cm tall) which, until last year, was growing happily in a pot on the terrace.  Because (a) the wind kept blowing it over and (b) we felt it was time to re-pot it into something bigger, we transferred it into a wooden tub (existing root-ball plus garden compost).

This spring, it started to bud copiously, but the leaves remained very small and have now practically shrivelled away.

We lifted it out of the tub and the roots have not started to grow out of the original ball.  The wooden tub has drainage holes and the compost has never been too wet or too dry.

I know this question has been asked before, but maybe someone has different suggestions.

[Robinia]

I'm no expert SteveD,only a keen amateur, so these are just ideas.
You say garden compost, meaning some that you've made yourself? Could there have possibly been any grubs in it that may have eaten any new roots that formed?  I've found this sometimes happens with home made compost & I don't usually use it for containers.
Also, acers in pots I believe, do better in acid compost, although they seem to do ok in my area without it when planted in the ground.
Apart from keeping it in a sheltered spot (we've had some awfully cold drying winds this year) I can't think of anything else.  Hope it recovers, they are beautiful aren't they?

[silly moo]

Did you tease out the roots from the root ball to encourage it to grow into the new compost?
Just an idea from a not very knowledgable gardener.

[SteveD]

Thanks very much for the replies.  I hoiked it out of the tub and there seemed to be a lot of ants around!

I tipped out all the compost (it was a mixture of home-made compost and commercial stuff) and replaced it with a mixture of rhododendron compost and general-purpose compost.

I carefully teased out the roots (which seemed to be viable), removing most of the "infested" compost, then replanted the tree in the tub, giving it a good water (the tub is well-drained).

I hope that the tree isn't too far gone to save.  Time will tell.