Moderate water for best flowering. Water deeply, then let the upper soil dry slightly; established plants tolerate short dry periods but need regular summer irrigation in Phoenix.
A heat-tolerant perennial commonly called Mexican petunia, with narrow leaves and abundant trumpet-shaped flowers. Ruellia brittoniana is a synonym of Ruellia simplex; mixed selections may include purple, pink, and white blooms.
Light: Full sun to partial shade; afternoon shade helps reduce stress in Phoenix’s intense summer heat.
Water: Moderate water for best flowering. Water deeply, then let the upper soil dry slightly; established plants tolerate short dry periods but need regular summer irrigation in Phoenix.
Soil: Adaptable to sandy, loamy, or clay soils, including alkaline soil; well-drained soil with some organic matter supports best growth.
Mature size: Typically 3–4 feet tall and 2–3 feet wide initially; spreads wider by underground stems. Dwarf selections remain smaller.
Bloom: Spring through fall, with possible flowering into winter during mild weather; each flower lasts about one day.
Evergreen / deciduous: Evergreen to semi-evergreen in sheltered Phoenix locations; frost may kill foliage and stems, with regrowth from roots in spring.