Styrax japonica .. flowering?

So I acquired a very nice Styrax japonica earlier this year. I've wanted one in my collection for quite some time and this happened along. The branchwork is rather nice and it'll be show-able in another year or two. What's a bit perplexing is the lack of information around about these. From what I've researched, they flower in late spring/early summer (June) on old wood (last years). However, the previous owner said this has only flowered once in the past 7 years or so and it doesn't seem to be contemplating flowering this year.

The questions I've pondering:
a) did I get the flower timing and old vs. new wood correct?
b) do they flower when rootbound or when the roots are loose?
c) I would dearly love to hear the regime of someone who has one that never fails to flower!

Thanks in advance..
-d