Purple Ruellia
Ruellia simplex
Rich purple blooms open fresh each morning from spring to fall, making it a reliable source of garden color and cut flowers.
Hardy in USDA zones 8-11; root-hardy in the low desert where frost knocks it back and it resprouts in spring, evergreen in the mildest winters.
AMWUA Notes
A tough, long-blooming perennial for moderate water; use sterile cultivars or deadhead to keep its reseeding in check.
Care Guide
Water weekly in summer to keep it blooming; it tolerates drought but flowers best with regular moisture and even handles periodically wet soil.
Shear back by a third to a half whenever it gets leggy to force fresh flowering stems; cut to the ground after frost to renew for spring.
A light spring feeding boosts bloom, though it flowers well without it.
Largely pest-free; its main drawback is aggressive spread by seed and rhizome, so deadhead to prevent it becoming weedy.
Blooms spring through fall and dies back in hard frost, returning quickly in spring; can seed around, so site where spread is welcome.
Soil, Feeding & Propagation
Adaptable to most soils including clay and periodically wet ground; tolerant of poor soil and even boggy spots.
Needs moderate soil.
Low feeder.
Division, cuttings, or seed; spreads aggressively by rhizomes and seed. Use sterile cultivars to limit spread.
1–1.5 ft
Spreads aggressively by rhizomes and self-seeding and can become weedy; contain it or plant sterile cultivars.
Placement Tips
- •Use its upright purple wands as a vertical color accent in beds and along walls.
- •Deadhead and confine it where you do not want its vigorous self-sowing to take over.
- •Group several for a mass of daily fresh blooms good for cutting.
- •Full sun to light shade; tolerant of heat and occasional wet spots near drainage.
Features
Best Uses
Ecological Value
Attracts
Companion Plants
Quick Stats
Design Styles
Include in Your Project
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Use this care guide to maintain your Purple Ruellia. Questions about your landscape? Reach out anytime.
Data from 2024 AMWUA “Landscape Plants for the Arizona Desert” guide.
Purple Ruellia — common questions
Answers for low-desert Phoenix conditions, drawn from this plant’s growing data.
How much water does Purple Ruellia need in Phoenix?
Purple Ruellia is a moderate-water perennial once established. Water weekly in summer to keep it blooming; it tolerates drought but flowers best with regular moisture and even handles periodically wet soil. A tough, long-blooming perennial for moderate water; use sterile cultivars or deadhead to keep its reseeding in check.
How big does Purple Ruellia get?
Expect roughly 2 ft tall and 1 ft wide at maturity, with a moderate growth rate. Allow about 1–1.5 ft of spacing when planting. Spreads aggressively by rhizomes and self-seeding and can become weedy; contain it or plant sterile cultivars.
Can you plant Purple Ruellia near a pool?
Yes. Purple Ruellia is considered pool-friendly, meaning it stays clean enough around water features and hardscape. Litter is rated low.
Can Purple Ruellia handle Arizona heat and winter frost?
Purple Ruellia is hardy in USDA 9-11 and wants full sun. Hardy in USDA zones 8-11; root-hardy in the low desert where frost knocks it back and it resprouts in spring, evergreen in the mildest winters. Blooms spring through fall and dies back in hard frost, returning quickly in spring; can seed around, so site where spread is welcome.
Does Purple Ruellia have thorns?
No. Purple Ruellia is thornless, so it is safe alongside walkways, patios and play areas.
Is Purple Ruellia safe around pets?
Purple 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 Purple Ruellia bloom in Arizona?
Purple Ruellia blooms in spring-fall, with purple flowers. The bloom draws bees, butterflies.
How much maintenance does Purple Ruellia need?
Purple Ruellia is low-maintenance. Leaf, flower and pod litter is rated low. Shear back by a third to a half whenever it gets leggy to force fresh flowering stems; cut to the ground after frost to renew for spring.
What kind of soil does Purple Ruellia need?
Adaptable to most soils including clay and periodically wet ground; tolerant of poor soil and even boggy spots. Nutrient needs are low. A light spring feeding boosts bloom, though it flowers well without it.
Is Purple Ruellia native to Arizona?
No. Purple Ruellia is not an Arizona native; it originates from the Mexico, West Indies, South America, but it is grown successfully in low-desert landscapes here.