Ruellia simplex

Mexican petunia, Mexican bluebell, Britton's wild petunia, Πετούνια, Πετούνια Μεξικάνικη, άγρια πετούνια του Britton. It is a native of Mexico, the Caribbean, and South America. It has become a widespread invasive plant in Florida, where it was likely introduced as an ornamental before 1933. Ruellia simplex is an evergreen perennial growing 3 ft (0.91 m) tall, forming colonies of stalks with lance-shaped leaves that are 6 to 12 in (15 to 30 cm) and .5 to .75 in (1.3 to 1.9 cm) wide. Trumpet shaped flowers are metallic blue to purple, with five petals, and 3 in (7.6 cm) wide. There is a dwarf variety that is only 1 ft (0.30 m) tall.

Ruellia simplex C.Wright is the oldest and accepted name for this species, which has been variously called Ruellia angustifolia (Nees) Lindau, Ruellia brittoniana Leonard, and Cryphiacanthus angustifolius Nees, among several synonyms. The genus is named after French botanist Jean Ruel, while the specific name refers to the simple, not compound leaves.

Ruellia simplex is native to Mexico, the West Indies, western Bolivia, southwestern Brazil, Paraguay, Uruguay, and northeastern Argentina. It has been widely used as an ornamental plant and has escaped from cultivation in the United States, Australia and parts of Asia, as well as several Pacific Islands. It has become invasive in some of these areas, forming dense, single-species stands of vegetation which threaten native plants. It is mainly a plant of wet places such as ditches, pond verges, lakesides and marshes, but can survive in drier conditions.

Not only is ruellia an evergreen, but it is a relatively hardy variety, despite its penchant for warmer temperatures. Although the care of ruellia plants indicates thriving in very warm climates, these wild petunia plants can actually survive winters in the 20’s and 30’s (-66 and 1 C.). Ruellia flowers will generally die back at the foliage tips below 32 degrees F. (0 C.) and all the way to the ground in the 20’s (-66 C.). However, upon a return to more seasonable temperatures, the ruellia wild petunia will bounce back with as much vigor as before.

An ideal location for growing ruellia is a site with full sun exposure. Although ruellia flowers are highly adaptable and may do well in shade, expect fewer blooms due to the lack of sunlight. Growing ruellia plants will appreciate regular water but, again, the tolerant plant can withstand drought conditions in prepared soil. This upright to spreading perennial can be propagated via seed, vegetative cuttings, or root divisions and should be trimmed to tame the self-seeding, rampant growth. Also, remove any frost damaged foliage to prevent any further damage or insipient disease.