Have had a winter sweet planted since it was a very young shrub, about 6-7 yrs now. Growth has been excellent, but still no blooms. Well drained location getting sun in summer from about 10:00 am - 2:00 pm. Have tried root pruning, pruning of branches, still nothing. Does it require far more sun to be successful, or something else? No one else I've talked to growths this. Purchased it from nursery on Vancouver Island and it blooms reliably for them. Your help appreciated.