Leave it be Nellie. You don't need to do anything. It will probably grow to about two feet tall and mine at least need no care at all. And it flowers all summer once it gets settled in.

Eventually they do get quite big and then they may be hard pruned to keep in bounds. Feed if you want more flowers.
Actually they self seed in my garden.

Mine have been in about 8 years and haven't got big, but the soil is not very good.

Is it getting at least a half day of sun, Nellie?

Thanks for all your help. Steragram i will take your advise and leave it be, hopefully next year there will be more flowers if i feed it as Owdboggy suggests, and yes to Tugbrethil it does get a good half day sunshine regards to all Nellie.

Mine flower well without feeding Nellie - such good tempered shrubs! Must try being kinder to them and see what happens!