Prefers fertile soil with moisture, but is very adaptable. After flowering, cut back stems about halfway for a new crop! Mexican petunia can be grown indoors as a houseplant in bright light. It is typically free of pests and disease.
Light: Sun to part shade. The quantity of blossoms is related to the amount of light the plant receives. The more direct sunlight the more flowers with fewer flowers appearing in overcast conditions or when grown in shadier conditions.
Moisture: Average to moist. Mexican petunia is a water plant that becomes very aggressive with access to abundant moisture. Survives dry spells once established. When growing Mexican petunia indoors water freely when in active growth but water only when dry in winter.
Hardiness: USDA Zones 8-10. Marginally hardy in Zone 7 if protected and mulched.
Propagation: Cuttings, division, seed. Stems are very easy to root in moist soil. Over time the plant multiplies and the original stem becomes a colony..
Use Mexican petunia towards the back of a flowering border, or as the centerpiece in a container. Plant next to pentas (Pentas lanceolata) for an effective contrast in both foliage and flower color and texture, with a purple verbena (Glandularia puchella)as ground cover below to mirror the larger, purple flowers of R. britonniana (the butterflies like this combination too!). The dwarf varieties also do well (and look great) in containers - especially those situated in hot sunny situations. The dwarf Mexican petunias also make a handy perennial edging plant for flowers beds and as colorful groundcovers.