Starter Live Plant Mexican Petunia Ruellia Brittoniana Flower Perennial Ship Bare roots/rooted cuttings, no pot Size: approx 6 inch Mexican-petunia is a perennial in zones 8 to 11 that stands up to 3 feet in height. Stems are green or purple and leaves are dark green, oppositely arranged and lance-shaped, roughly 6 to 12 inches long and to inches wide. Veins are prominent on the underside of the leaf. Leaf margins are can be smooth or wavy. Mexican petunia grows and blooms best in full sun or partial shade. It will grow in shade, but doesn't bloom as much and looks leggy and lanky. This sun-loving perennial likes rich, slightly moist soil so mulch the plants to maintain consistent soil conditions, especially during hot, dry weather. In the North, Mexican petunia can be grown as an annual flower. Mexican petunia can become a fast spreader -- so plant it where you can control its spread.