this was the only info i could readily find about your plant:
>will grow in full sun but will also flower prolifically in dappled or half-day shade
Philadelphus are not fussy as to soil type
protect from strong wind
normal watering, fertilising and mulching to give best results
prune after flowering by removing some of the oldest basal canes so new canes can develop. Shorten the remaining canes to encourage stronger laterals which give rise to next spring's display.
kinda makes it sound like if you prune it, it will bloom