Ruellia flowers are 2 inch (5 cm.) long, funnel-shaped blooms growing on a perennial shrub. Originally native to Mexico, it is now found in the southwest United States, naturalized in many areas.

Care of Ruellia
Not only is ruellia an evergreen, but it is a relatively hardy variety, despite its penchant for warmer temperatures. Although the care of ruellia plants indicates thriving in very warm climates, these wild petunia plants can actually survive winters in the 20's and 30's (-66 and 1 C.). Ruellia flowers will generally die back at the foliage tips below 32 degrees F. (0 C.) and all the way to the ground in the 20's (-66 C.).

Light
Mexican petunias love sunshine and will thrive in full sun. They also grow quite well in partially shaded areas, but shade reduces flower production. Plants grown in full sun will have purple stems while those grown in the shade will have green stems.

Soil
These hardy plants can be grown in almost any soil type but do the best in well-draining, rich soil.

Water
Mexican petunias are resilient when it comes to water intake, as they can survive both droughts and floods. During the growing season, it is best to keep the soil evenly moist, watering only once the soil begins to dry out. For the winter months, reduce watering until the soil is dry.