Scientific: Ruellia longepetiolata (Synonyms: Dipteracanthus longepetiolatus, Ruellia humifusa, Ruellia squarrosa)
Taxonomic re-assessment: Ruellia taxon in the new world are currently undergoing a somewhat major reclassification based on ddRAD molecular sequence data to reconstruct phylogenetic relationships.
Common: creeping ruellia, trailing ruellia, water bluebell
Family: Acanthaceae
Origin: Mexican states of Querétaro, Veracruz, and Puebla.
Invasive Alert: Purple ruellia has escaped from cultivation in El Salvador, New South Wales, Queensland, Réunion.
Pronounciation: Ru-EL-lee-a lon-ge-pe-tee-o-LAY-ta
Hardiness zones
Sunset 13-24
USDA 9-10 (with cold protection), 11
Landscape Use: Small-scale ground cover for cold protected, mostly shaded sites, large open air atriums, patio or entryway containers or planter beds, raised planters and borders, subtle flower accent.
Form & Character: Low and spreading, subtropical, diminuative, lush, tender with occassional color surprises.
Growth Habit: Evergreen (in Phoenix), herbaceous, perennial broadleaf subshrub, moderately prostrate to only 6-inches tall and 3-feet wide, stoloniferous, adventitious roots can develop from stolons upon ground contact.
Foliage/Texture: Leaves opposite, elongate-lanceolate to 3-inches long, mildly pubescent, distinct pinnate veination on abaxial surface; medium texture.
Flowers & Fruits: Flowers terminal on elongated, axillary peduncles, corolla to 1-inch long, tube about 0.5-inches across, expanded above, lobes rounded, flower colors are mostly violet purple, but also white or pink. Fruits are inconspicuous brown achenes.
Seasonal Color: Very subtle violet flowers color throughout the year.
Temperature: Freeze and high heat intolerant.
Light: Partial to full shade, absolutenly NO western sun.
Soil: Tolerant of some alkalinity, but prefers acidic to neutral soils.
Watering: Requires regular and frequent irrigations especially during summer.
Pruning: Little to none.
Propagation: Cutting, seed.
Disease and pests: Spider mites
Additional comments: Creeping ruellia absolutely requires significant protection from temperature and sunlight extremes in Phoenix. As such its use potential is heavily parameterized by the environment and is thus infrequently seen.
