My variegated weigelia is 2 years old this summer and I am enjoying it. I'm not so sure about the growth, though - but maybe it's just my own aesthetic preference: As you can see in the picture, it has a single, very tall vertical branch and I'm not sure it I should cut it back (next spring?) so that it is more compact - or if the rest of the bush will eventually catch up with the single stalk, so I should just leave it alone, even if it looks a bit strange at the moment?
It is a very good idea to prune them. There are several things to know before you do, though. This is not the easiest shrub to prune. Here is an article that will help:
This collection of articles will help also: