Hedges for Warm climate?

I would suggest either Gardenias or Ligustrums. Both can handle the cold and will take the heat. I lived in the Orlando area for 25 years and had good luck with both of them.

You can try viburnum, but it will only do dappled shade. I'm unaware of any deep shade shrubs that will perform like you want. You basically need direct sunlight if you want flowers.

You can also try planting clumps of differently colored coleus in that spot. They do full shade and have very interestingly colored leaves that may act as a stand-in for flowers.

http://4.bp.blogspot.com/_mIVYqdxx_e0/TQxLaAlYhMI/...

I would suggest wax myrtle... but no blooms...

The colourful shrubs I'd recommend drop their leaves... but... I like buckeye, beauty berry, strawberry bush... also vitex, and even buddleia....

In Florida, if you are willing to move away from the traditional shrubs, I would totally recommend datura wrightii, and any of the brugmansias... the brugs get kinda large, but they are traffic-stoppers!

Why don't you try cannas, flowering ginger, or bird of paradise? Not shrubs, but shrubs are over-used.... Time to move on...