Royal poinciana is very fast growing, about 5 ft (1.5 m) per year until maturity. It's best to provide protection from strong winds. Royal poinciana is drought tolerant, but does best with regular water in the growing season and very little water in its dormant season.
Royal poinciana is a spectacular shade tree in tropical climates. As a free standing specimen tree, it has no peers. Picture this beauty framed by a cluster of coconut palms! Royal poinciana tolerates salty conditions and can be grown near the coast, but not in openly exposed beach conditions. Royal poinciana tolerates hard pruning and can be kept at a small size, and even grown in the greenhouse.
Yes, there are down sides. Royal poinciana has shallow, wide-spreading roots that will not allow underplanting and the roots can be a threat to building foundations and sidewalks. The tree sheds large woody pods and brittle branches that get broken off in the wind. Seedlings will come up all around the tree.