Whats best time to prune or trim acer?

Question

my acer is 10ft tall and spindley, a branch broke off and the tree is out of shape. i wish to cut back to about 6ft, when should i do this

Answer 1

Like most deciduous trees the plant will be easier to prune in the winter or early spring before leaf break.

Answer 2

from late october and before end november

Answer 3

Here is a link to the RHS advice on Acer pruning.  I pruned a large specimen for a client recently and took a photo of it first then drew on the photo the rough shape I wanted to achieve then referred back to that during pruning - sounds mad but it really helped to keep a balanced and natural shape.  Good luck :-)