are you referring to osmanthus fragrans (tea olive)?
if so, they are fall-bloomers.
your shrubs may not have bloomed last year because of being transplanted or the age of the shrub.

Actually, they do bloom in the spring where there's mild winters is such as Houston. My mother's was blooming when I was down there last weekend. Where I live... winter was very harsh on mine. No blooms so far and lost all of the leaves last month so they are starting over with new leaves fortunately.

Stephan,
The major factors for swet tea olives to bloom from what I have seen are sunshine, water and humidity and mulching.
They love full sun, so they will bloom better and more often with alot of sunshine.
They can't be allowed to go without water for more than a week, and when you water them, spray thier leaves too.
They need mulch (good pine mulch) around the base of the shrub or tree, a good 2-3 inches for the summer season. If you don't mulch them, don't plant them.
If you have already done the above essentials, try feeding them this year. I use diluted Miracle Grow once a month for them, they love it.
Good luck, I hope they will be blooming for you in April.
Mine bloom off and on all summer, but heavy in the spring and really heavy bloom in the fall.

We have just one Osmanthus fragrans, though our neighbor has several. All are blooming like crazy right now. And it's become too cold (again) to sit outside, drats!

Ours blooms off and on all throughout the spring and into late fall.

Are these containerized plants or in-ground?