Mexican Petunia (Ruellia tweediana): Tough Perennial with Purple Trumpets

Mexican petunia (Ruellia tweediana, often sold as R. brittoniana), also called desert petunia or Florida bluebells, is a resilient, clump-forming perennial that bears petunia-like purple flowers on tall, purplish stems from late spring to frost. The lance-shaped leaves are dark green with a metallic sheen.

Growth Habit

Plants reach 3–4 feet tall and spread aggressively via rhizomes and self-seeding, forming dense colonies. It thrives in wet or dry conditions, sun or shade, making it a bulletproof choice for difficult sites. However, it can be invasive in some regions (check local guidelines).

Care

Adaptable to most soils and moisture levels. Full sun produces the most flowers. Cut back after flowering to control spread and encourage rebloom. In zones 8–11, it is perennial; elsewhere, grow as an annual.

Taxonomy

• Family: Acanthaceae
• Genus: Ruellia
• Species: tweediana
• Synonyms: Ruellia brittoniana, Ruellia coerulea, Ruellia ignorantiae, Ruellia microphylla, Ruellia spectabilis