Mexican petunia

Ruellia simplex

Tall Mexican perennial with narrow dark green leaves and continuous deep violet (or pink or white) petunia-like flowers through warm months. Each flower lasts a day; successive buds keep continuous bloom.

Hardiness ratings

Mexican petunia hardiness across the four zone systems
SystemRatingTemperature rangeHow to read it
USDA hardiness zone Zone 8–11 −12.2 °C to 10 °C Plant tolerates down to this zone
RHS hardiness rating H3 −5 °C to 1 °C Plant needs at least this level of cold tolerance
Canadian plant hardiness zone Zone 9 −1 °C and warmer Plant tolerates down to this zone
Australian (ANBG) zone Zone 3–7 −5 °C and warmer Plant tolerates down to this zone

Growing notes

  • Native to Mexico but now naturalised throughout tropical and subtropical regions worldwide
  • WARNING: Listed INVASIVE in the southeastern US (especially Florida and Texas) and parts of Australia — escapes via seed and rhizome, do not plant in those regions; sterile cultivars (‘Mayan Purple’, ‘Purple Showers’) are safer alternatives
  • Drought tolerant once established, tolerates wet soils and shade — adaptable to extreme conditions
  • Distinct from common garden petunia (Petunia) — Ruellia is a separate genus with longer-lasting flowers

Categories

Related plants

Cross-check Mexican petunia against your zones

Reference

Mexican petunia on Wikipedia