Desert Cassia produces yellow flowers about an inch in diameter. Heaviest flowering occurs during the period from October to May, but blossoms may also pop open at other times of the year. A sunny exposure yields the most prolific flowering. Since S. polyphylla is found natively at elevations from near sea level to nearly 1,000 ft., it is capable of withstanding a bit more cold than other Sennas. It isĀ  a host plant for the Sulphur Butterfly, and a nectar source for all of our butterflies.