You can prune it back now, but I wouldn't take more than a half of the bush, preferably a third, if its large, and then prune back by another third next year if its really out of hand. Now is the time to take semi ripe cuttings for rooting, so select those first, before you prune it all back.

Thank you, it is not a large bush in fact it is quite a skinny looking bush that is why I thought if I pruned it it may come on good next year.