QuestionsHow to growTrees and ShrubsPruningHow to prune philadelphus 0 Vote Up Vote Down Bridget Stanley asked 15 years ago How do I prune philadelphus? I have had my plant for three year and this was the first year it produced any flowers and there were very few of them about eight in total. 1 Answers 0 Vote Up Vote Down Gerry Daly Staff answered 6 years ago It is still young … leave it be for a few years and then shorten shoots a little and thin out a little each year after flowering.