The Mexican Petunia, the Texas Petunia, or Purple Ruellia, is a shrubby perennial with a woody base and dark green leaves with purple stems. Its dark purple flowers attract bees, butterflies, and hummingbirds. This shrub can survive brutal heat, humidity, and drought. It reseeds readily and spreads quickly. This plant is so tough and good at spreading with itself that it can become invasive if left unmanaged in warm, moist areas.

It can withstand drought but does best in medium to wet soil in full sun to part shade. Almost entirely pest and disease-free. Cut back stems after flowering to encourage new growth.