AusBonsai

Hello I came home last night to find a branch broken on my large wisteria! I cannot see any borer so am putting it down to the fact it has become too heavy. Could you please advise me if I can cut back the old branches, when to do and how far back. I have never cut back so am unsure how far to go. Will the cut back hurt my tree? Many thanks. The broken branch is on the right bottom of tree.

You can cut wisteria back as hard as you like.
If the branch has broken, cut back to the break and it will reshoot.

A branch on a bonsai will not break because it is too heavy, so must have been bumped or bashed if there is no other cause

Ken

Ditto, cut everything back as hard as you like. At this time of year it is at its strongest growth cycle and as ken wrote it will re shoot vigorously as long as it is well watered, well fed and in good sunshine. It looks like it needs to be compacted a bit.

Do wisterias need a general cutback to produce back buds on lower branches?
Several times I have tried to force budding on my large wisteria by cutting back just 1 branch and each time the bit left just died back to the nearest fork. I finally got buds by cutting all branches at the same time.

Thanks everyone I have been reluctant to cut as it has really been beautiful but I guess the time has come. First time flowering this year. IF I cut back hard will it stop it flowering for a while? this is very informative and I do thank you all for you input. Most appreciated.

If you cut back now, it should still flower again next year, If you were to wait until after christmas then probably it will not flower.

Ken