Scientific: Ruellia brittoniana (synonym R. malacosperma)
Common: purple ruellia
Family: Acanthaceae
Origin: Mexico

Pronounciation: Ru-EL-lee-a brit-toe-nee-A-na

Hardiness zones
USDA 8 (freeze damage), 9-11

Landscape Use: Foliar and floral accent and/or filler shrub for landscape borders, even streetscapes. Versatile shrub for use in mesic and oasis landscape design themes. Works well with Spanish architecture.

Form & Character: Mostly herbaceous perennial shrub, dark purple cast, succulent appearance, tropical.

Growth Habit: Shrubby and unruly, quick to establish and grow to 3 to 6 feet with equal spread. Becomes lush and full with age. Spreads to form clumping colonies by underground rhizomes.

Foliage/texture: Leaves elongate-linear to 12 inches, much shorted if plants are grown in dry site, entire to undulate, petioles to 3/4 inch long; medium texture.

Flowers & fruits: Flowers terminal on elongated, axillary peduncles, corolla to 1.5 inches long, tube about 0.5 inches across, expanded above, lobes rounded, flower colors are mostly violet purple, but also white or pink. Ruellia flowers attract bees. Fruits are inconspicuous brown achenes; however fruits eject seeds up to 10 feet from the plant when sprayed with a hose, or rained upon (sounds like Rice Krispies when first doused with milk).

Seasonal color: Deep purple foliage is colorful year round. In Phoenix, purple, white, or pink, flowers are produced in all but coldest but winter.

Temperature: Freeze intolerant, but heat loving, except for dwarf cultivars which might need some protection from west summer exposures when young.

Light: Full sun to partial shade

Soil: Tolerant of some alkalinity, but prefers acidic to neutral soils.

Watering: This shrub is very responsive to landscape irrigation. Thrives with regular and frequent irrigations especially during summer.

Pruning: Prune to shape anytime. Except for dwarf cultivars, often headed back severely to the ground in winter.

Propagation: Cutting, seed

Disease and pests: Spider mites

Additional comments: Escaped from cultivation in SE US. Popular cultivar ' Katie' is dwarf 10 to 12 inches tall, with violet flowers. Best used with drip irrigation. In flood irrigated landscapes, this shrub might become invasive. Dwarf pink ('Chi Chi') and white ('Alba') flowering cultivars are available. Works well with Tecoma stans, Bougainvillea, and many others with complementary flower colors for a tropical landscape feel.