Winter pruning of wisteria 

Remove the longer summer growth shoots unless you wish to train them into new areas to increase the coverage of the wisteria against a wall or on a pergola. 

Pruning in the winter once the leaves has fallen makes it a lot easier to see the longer summer growth shoots that need to be removed

Ideally with the pruning you need to leave the stems with shorter stubby shoots which as the flowering spurs and will produce the flowers in the flowing spring and summer. 

Once the flowering buds start to break into flower looking similar to catkins its a good time to feed with a high potash plant food such as tomato feed to help the wisteria with flowering.