Posted: 16/07/2016 at 21:01
You need to prune it next March. Take out the thickest branch, which seems to be on the right hand side. Cut it down to six inches (15 cm). It will then form new shoots which will flower in 2018. In 2018, cut down the other branch, which will shoot and flower 2019. Feed it with a rose fertiliser in March,and mulch with Farm yard manure if you can get it or compost, and give it a bucket of water every week that it has not rained as it may be dry against the wall.
In subsequent years take out the oldest shoot, so that is has a self regenerating cycle and you don't just get flowers at the top.
If you have a very long shoot, tying it down to the horizontal will induce it to flower.