On 17 Jan, 23:49, "The Old OakTree" wrote:
It's been growing on the wall of my garage (south-facing) for
about 10-12 years, and has never flowered, though it produces
plenty of leaves.
Any suggestions?

To add to pk fabulous response, here some visual for winter pruning. I
assume, since you haven't mention it, that you perhaps haven't pruned
correctly. This is usually the most common cause of non-flowering
wisterias, as I found myself )

http://www.videojug.com/film/how-to-...eria-in-winter