Despite the name, this plant is not related to the usual garden petunia at all - rather, it belongs to the ruellia genus. Desert petunia is an extremely tough, drought-resistant plant with a long bloom period. is a tender evergreen perennial that forms colonies of stemmy stalks standing 3 ft in height and of indeterminate width. The strong semi-woody stalks are distinctly vertical in aspect and hold attractive dark green, leaves oppositely at the nodes. The lance-shaped leaves are to 6-12 in in length and 1.3-1.9 cm wide. When grown under hot sunny conditions the foliage assumes a metallic bluish cast. The blossoms are blue, trumpet shaped and about 1.5-2 in in diameter and are borne at the tips of the stems. Varieties with white, pink, and many shades of blue are available, as are dwarf versions that form clumps that are about 8-12 in in height.