Answer: Mockorange shrubs (Philadelphus coronarius) are an old time favorite for their fragrant blooms. The most common reason for this plant to fail to bloom is improper pruning. The plant blooms on old wood from the previous year, so pruning should only be done immediately after flowering, which would normally be in June.
Mock orange, in my experience is a long lived and well loved old garden favorite and yet it can be slow to come into flower as a young plant. They prefer sun and a decent soil, bloom for about a week, and then take care of themselves for the rest of the year.
Since it sounds like your plant is otherwise healthy and doing well, I think I would just sit tight for another year or two! The fragrance should be worth the wait.
There are links to several photos at the following web address:
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