I wouldn't worry about the soil too much unless your soil is too acidic (If you do need to amend the soil, add some lime to the mix before planting. You could also add wood ashes after you plant to maintain the alkalinity of the soil.

They are extremely hardy plants. They really don't need any special care after being planted. They may take a drink of water once a month in summer (that's here in Arizona), otherwise trim them back to the ground every winter, and they will grow back and flower profusely. Also, keep the seed pods out of the reach of children and pets because they are poisonous.

Hope this helps

TN -
I lived in Okaloosa county for 10 years before movint to NM. Your soil is VERY acidic (4.5 ish) Here the soil is alkaline. We also don't have the humidity here tha Florida has, or the almost daily spring rains.
I'm not sure these plants will like Florida.

The above poster may be on to something. Here in Phoenix we use the red Mexican bird of Paradise as a freeway planting where temperatures can get as high as 160 degrees near the pavement with single digit humidity and full sun all day long. They simply love that type of environment. Bougainvillea is also grown along hundreds of miles of freeways around here and it loves that type of environment as well. Your climate may be too wet and not hot enough...