Desert Petunia, Florida Bluebells, Mexican Petunia, Mexican Blue Bells 'Katie Blue'

Ruellia brittoniana

Family: Acanthaceae (ah-kanth-AY-see-ee) (Info)
Genus: Ruellia (roo-EL-ee-uh) (Info)
Species: brittoniana (brit-toh-nee-AY-na) (Info)
Cultivar: Katie Blue




Foliage Color:

Unknown - Tell us

Bloom Characteristics:

This plant is attractive to bees, butterflies and/or birds

Water Requirements:

Drought-tolerant; suitable for xeriscaping

Where to Grow:

Unknown - Tell us


6-12 in. (15-30 cm)


12-15 in. (30-38 cm)


USDA Zone 7a: to -17.7 C (0 F)

Sun Exposure:

Full Sun

Sun to Partial Shade



Bloom Color:


Bloom Time:

Mid Spring

Late Spring/Early Summer

Mid Summer

Late Summer/Early Fall

Mid Fall

Blooms repeatedly


Grown for foliage


Other details:

May be a noxious weed or invasive

Soil pH requirements:

Unknown - Tell us

Patent Information:

Unknown - Tell us

Propagation Methods:

From herbaceous stem cuttings

From seed; direct sow outdoors in fall

Self-sows freely; deadhead if you do not want volunteer seedlings next season

Seed Collecting:

Allow pods to dry on plant; break open to collect seeds


This plant has been said to grow in the following regions:

Phoenix, Arizona

Scottsdale, Arizona

Cabot, Arkansas

Barbourville, Kentucky

Evans, Louisiana

New Orleans, Louisiana

Barnsdall, Oklahoma

Stilwell, Oklahoma

Conway, South Carolina

Baytown, Texas

Bryan, Texas

Cleburne, Texas

Corpus Christi, Texas

Fort Worth, Texas

Garland, Texas

Houston, Texas

Missouri City, Texas

Port Lavaca, Texas

San Angelo, Texas

San Antonio, Texas

San Marcos, Texas

Spring, Texas

Wells, Texas

show all

Gardeners' Notes:


On Mar 28, 2016, coriaceous from ROSLINDALE, MA wrote:

This species both self-sows weedily and also spreads underground aggressively by rhizomes.

The Florida Exotic Pest Plant Council has listed this species as a Category l invasive, because it has been found to invade natural areas and displace native flora. The species is native to Mexico, South America, and the Caribbean. It has naturalized from Texas to South Carolina.

The accepted name for the species is Ruellia simplex. Synonyms include:
Ruellia brittoniana
R. coerulea
R. malacosperma
R. tweediana


On Sep 6, 2015, siege2055 from Stilwell, OK (Zone 7a) wrote:

I really like this one as its hard to find tough, reblooming plants that have blue flowers. I cant comment on its hardiness yet, but it is easy to propagate by sticking a stem in a glass of water, and forms roots in about a week. I have heard the seeds can germinate from Katie, and I would like to know if the seedlings revert to the tall wild species type or stay small like Katie. I would actually like to have some of the tall, and have collected some viable looking seeds from it to sprout later. I dont think invasiveness would be an issue here.


On Feb 28, 2015, poeciliopsis from Phoenix, AZ wrote:

Central Phoenix -- Katie blue Ruellia brittoniana is a very tough plant. It grows in the ground in our garden in a harsh location -- a narrow bed between a concrete walk and a brick patio, in full sun in summer and partial shade in winter. For many years it was watered sporadically, but is now on a drip system and has become more robust. We cover it during the hardest freezes, because below 30 the tops will be damaged. During our coldest winters (lows in mid 20s F) it has sometimes sustained substantial damage, but has bounced back.


On May 1, 2013, YeeFam from Leander, TX (Zone 8a) wrote:

This variety is short mounding plants when grown in bright shade to full sun. In shade, bit taller and broader leaves.

I have them growing in beds around trees and bushes - nice ground cover if that is what you need/want.

Once established - will tolerate drought - evergreen in Tomball, TX (northwest of Houston, TX).

Have some growing in containers - doing very nicely -


On Apr 11, 2012, mig0007 from Houston, TX (Zone 8b) wrote:

I too was awed by the fantastic show of purple flowers...then the second year came around and before I actually realized it, the plant doubled in size and started sending up shoots 1-2 feet away. I tried to keep it in check but it became a constant battle. I just came in from digging a hole about 5 foot around and 18 inches deep. This was how big the root structure got in 2 years...from now on, if I want to have another one, it will forever remain in a planter.


On Oct 12, 2010, aggiebot5 from College Station, TX wrote:

I must second the evil/invasive comment below. This plant is escaping and becoming established and problematic in the Houston area. It's gorgeous, but we really don't need another exotic weed in Texas.


On Jun 29, 2010, FernByron from San Antonio, TX (Zone 8a) wrote:

I once had a thriving fern garden on the shady side of the house. I added a four Mexican Petunias to add a few flowers. They were located off to a corner. Two years later---I had a full, thriving garden of these and only a few ferns. Be careful where you plant this harmless little plant. It is evil and subtle. SAN ANTONIO, TX