Senna surattensis (the newest botanical name) is a very common, fast growing tree that will do well in zone 10A as long as the bugs don't get to it. They grow to around 20' with a 15' spread and bloom most of the year. There are many much more interesting trees with yellow flowers (if that's the requirement). Some are much larger though and I'd hate to make a recommendation without knowing just how tall a tree you desire.

The Lee County extension service seems to like it

http://lee.ifas.ufl.edu/Hort/GardenPubsAZ/Sennasurattensisglaucouscassia.pdf

Many years ago, in Landscape 101, we developed a list of ground-covers, shrubs, and trees that were in common use, overuse for that matter. It was called "The Gas Station" list because if you were going to landscape a gas station, you wanted plant material that could a) grow in concrete with no irrigation, b) withstand vehicular damage, and c) cost next to nothing. Cassias were the number one choice for a flowering tree from that list.

Personally, I don't like the tree. I think it gets ratty without constant maintenance and it always seems to be full of one bug or another. Even though they grow a bit taller and don't bloom as often, I used more Yellow Tabebuias than Cassias and would recommend that instead of the Cassia to the original poster.

My favorite yellow tree, and it's a large sprawling one, has always been the Tipuana tipu. It rarely goes completely deciduous, blooms twice a year, and has a controllable root system.

Y'all use Cassia didymobotrya down there? This species-the "popcorn cassia", has been just plain great in my use of it way up here as an annual "thriller" in the center of large planters. I need to record a message for all the folks calling in inquiring as to what that big yellow thing is! Maybe it's passe' in Florida, but up here, it's a real winner.

Fawnridge, thanks so much for your expertise and insight. I'll certainly take your advice into consideration. You and this board are a wealth of knowledge.

Dirtygardner73, thank you for the link. I've been doing so much research, I think I've overwhelmed myself, LOL. But it's all good.