Rainbow Shower Tree is a hybri d between Amaltas (Cassia fistula) and Java cassia (Cassia javanica). It is a gorgeous tree having clusters of flowers with various colors. There are several different varieties of the rainbow shower tree, each having different colors of flowers, often maturing from one color to another. While there is more colorful variety having clusters of yellow and pink flowers, there is also a variety with nearly white flowers, with a tinge of yellow. It is a medium to large size tree. The tree is very drought tolerant and grows best in full sun, hot, and dry conditions.