Ruellia, Genus, humilis, Species,
- Genus & species
hairy ruellia
Overview
Ruellia humilis, hairy ruellia or wild petunia, is a low, hairy herbaceous perennial in the acanthus family, growing 6-24 inches (15-60 cm) tall and wide with upright to sprawling stems. The opposite, oval leaves are 1-2.5 inches (2.5-6 cm) long and covered, like the stems, in soft hairs. From early summer into fall it produces funnel-shaped lavender to pale purple flowers 2-3 inches (5-8 cm) long that resemble petunias; each flower opens in the morning and drops by the end of the day. It grows on dry prairies, glades, rocky open woods, and roadsides across the central and eastern United States, spreading slowly by seed. As a prairie plant it tolerates heat, drought, and poor soil once established, though it can self-sow widely in a garden. R. humilis is grown in native and prairie plantings, rock gardens, and dry borders, and it is a larval host for the common buckeye butterfly.
Native Range
Ruellia humilis is native to the central and eastern United States, from the Great Lakes and Pennsylvania south to the Gulf states and west to Texas and Nebraska. It grows on dry prairies, limestone glades, rocky open woods, and roadsides. It is widespread through the Midwest and Southeast.Suggested Uses
Hairy ruellia is grown in prairie and native plantings, rock gardens, dry borders, and as a low groundcover in sunny, dry sites. It is a larval host for the common buckeye butterfly and draws bees and other pollinators to its flowers. Its drought tolerance makes it useful in low-water and naturalized plantings.How to Identify
Appearance
Size & Dimensions
Height6" - 2'
Width/Spread1' - 1'6"
Bloom Information
Detailed Descriptions
Flower Description
Lavender to pale purpleFoliage Description
GreenGrowing Conditions
Sun Requirements
Requires 6-12 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Grow hairy ruellia in full sun to part shade on dry to medium, well-drained soil, including sandy, rocky, and clay soils. Once established it tolerates heat, drought, and poor ground and needs little water. It grows in a tidy mound in lean soil but stretches and sprawls in rich or shaded conditions. It is hardy in USDA zones 4-8 and dies back to the crown each winter, returning in spring. It self-sows readily, so removing seed capsules limits unwanted seedlings. It has few pests and diseases.Pruning
Cut the dead stems back in late winter or early spring. Trimming plants in early summer keeps them compact but delays flowering. Remove seed capsules before they ripen to limit self-sowing.Pruning Schedule
Prune: March
early spring
Container Growing
Suitable for container growing
Minimum container size: 2 gallons
