Katie Ruellia
Ruellia simplex Katie
A fragrant purple-flowering groundcover that attracts bees and pollinators throughout the warm season.
A root-hardy perennial in USDA zones 8-11 that dies back in the low 20s°F and returns each spring, thriving in low-desert heat and tolerating both drought and occasional wet soil.
AMWUA Notes
A well-behaved dwarf ruellia; unlike its tall relative it sets little viable seed, so it will not colonize the garden.
Care Guide
Water every 7-10 days in summer for steady bloom; this compact dwarf ruellia tolerates a range of moisture and even brief flooding but keeps flowering best with regular water.
Shear off spent blooms and tidy the clump through the season, then cut back to a few inches in late winter to remove frost damage; unlike the tall species it is a sterile, non-seeding dwarf.
Feed lightly in spring; it blooms freely without heavy fertilizing.
Largely pest-free; avoid confusing it with the invasive tall Mexican petunia, which seeds aggressively.
Purple funnel flowers appear spring through fall; foliage freezes back in the low 20s°F and resprouts reliably from the crown in spring.
Soil, Feeding & Propagation
Adaptable to most soils including clay and periodically wet ground; tolerates poor drainage and brief flooding better than most groundcovers.
Needs moderate soil.
Low feeder.
Division of clumps or softwood cuttings; the dwarf Katie is sterile and sets little viable seed.
1.5-2 ft on center for a low mounding mass
Well-behaved clumping roots; unlike the invasive tall Mexican petunia it does not colonize by seed.
Placement Tips
- •Space 18-24 in apart for a low mounding mass in pollinator and color beds.
- •A tidy, non-seeding front-of-border edge that stays compact around walks and patios.
- •Tolerates poorly drained and periodically wet spots better than most groundcovers.
- •Plant in full sun to light shade; bloom is heaviest in full sun.
Features
Best Uses
Ecological Value
Attracts
Wildlife Value
Companion Plants
Quick Stats
Design Styles
Include in Your Project
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Use this care guide to maintain your Katie Ruellia. Questions about your landscape? Reach out anytime.
Data from 2024 AMWUA “Landscape Plants for the Arizona Desert” guide.
Katie Ruellia — common questions
Answers for low-desert Phoenix conditions, drawn from this plant’s growing data.
How much water does Katie Ruellia need in Phoenix?
Katie Ruellia is a moderate-water groundcover once established. Water every 7-10 days in summer for steady bloom; this compact dwarf ruellia tolerates a range of moisture and even brief flooding but keeps flowering best with regular water. A well-behaved dwarf ruellia; unlike its tall relative it sets little viable seed, so it will not colonize the garden.
How big does Katie Ruellia get?
Expect roughly 2 ft tall and 4 ft wide at maturity, with a moderate growth rate. Allow about 1.5-2 ft on center for a low mounding mass of spacing when planting. Well-behaved clumping roots; unlike the invasive tall Mexican petunia it does not colonize by seed.
Can you plant Katie Ruellia near a pool?
Yes. Katie Ruellia is considered pool-friendly, meaning it stays clean enough around water features and hardscape. Litter is rated low.
Can Katie Ruellia handle Arizona heat and winter frost?
Katie Ruellia is hardy in USDA 9-11 and wants full sun. A root-hardy perennial in USDA zones 8-11 that dies back in the low 20s°F and returns each spring, thriving in low-desert heat and tolerating both drought and occasional wet soil. Purple funnel flowers appear spring through fall; foliage freezes back in the low 20s°F and resprouts reliably from the crown in spring.
Does Katie Ruellia have thorns?
No. Katie Ruellia is thornless, so it is safe alongside walkways, patios and play areas.
Is Katie Ruellia safe around pets?
Katie Ruellia is listed as pet-friendly in this guide. If your dog is a determined chewer, check any new plant with your vet before planting.
When does Katie Ruellia bloom in Arizona?
Katie Ruellia blooms in spring-fall, with purple flowers. The flowers are fragrant. The bloom draws bees, butterflies.
How much maintenance does Katie Ruellia need?
Katie Ruellia is low-maintenance. Leaf, flower and pod litter is rated low. Shear off spent blooms and tidy the clump through the season, then cut back to a few inches in late winter to remove frost damage; unlike the tall species it is a sterile, non-seeding dwarf.
What kind of soil does Katie Ruellia need?
Adaptable to most soils including clay and periodically wet ground; tolerates poor drainage and brief flooding better than most groundcovers. Nutrient needs are low. Feed lightly in spring; it blooms freely without heavy fertilizing.
Is Katie Ruellia native to Arizona?
No. Katie Ruellia is not an Arizona native; it originates from the Horticultural cultivar, but it is grown successfully in low-desert landscapes here.