Seeds from this Texas Flowery Senna, Flowering Senna, Flowery Senna, Tree Senna, Argentina Senna, Buttercup Bush. This evergreen shrub produced these gorgeous masses of bright yellow clumps of blossoms both in early spring and late fall. This plant is a very fast grower will not take too long to blossom from seed and is hardy in zones 8a to 11. Another real show stopper for the neighbors It grows 5 to 6 feet tall and 6 feet across. Somewhat drought tolerant and likes full sun but will tolerate part shade with fewer blooms.