Did it ever bloom? We ignore ours and when it gets ready it blooms- it does best in full sun, just gets tall if shaded, only gets rain watered, unless like last yr the drought was so awful we watered some to keep the trees from dying onto the house.
When was it planted? If it was just planted recently (this year or last year) then it probably just needs to finish getting established before it'll bloom. Otherwise if it's been in the ground for years then I'd have the same question about whether it's ever bloomed--if it has bloomed in the past but not this year then I'd look at what changed this year (either in how you've cared for it, or weather/climate conditions). If it's been around for years and has never bloomed, then I'd look at things like whether it gets enough sun. Also, too much nitrogen fertilizer can stimulate lots of green growth at the expense of blooms, so maybe lay off the fertilizer a bit next year and see if that helps.