Ruellia simplex (Mexican Petunia)

Ruellia simplex (Mexican Petunia) from Walley Morse on 4-15-12, #86-54.

Mexican Petunia, Mexican Blue Bells, Florida Blue Bells, Desert Petunia, Etc.

Ruellia simplex

roo-EL-ee-ah SIM-plecks


Ruellia brittoniana

roo-EL-ee-ah brit-toh-nee-ay-na

Synonyms of Ruellia simplex (11) (updated on 11-5-22 from Plants of the World Online): Arrhostoxylum microphyllum Nees, Cryphiacanthus angustifolius Nees, Ruellia angustifolia (Nees) Lindau, Ruellia brittoniana Leonard, Ruellia coerulea Morong, Ruellia ignorantiae Herter, Ruellia longipes Urb., Ruellia malacosperma Greenm., Ruellia microphylla (Nees) Lindau, Ruellia spectabilis Britton, Ruellia tweedyana Griseb.

Ruellia simplex C.Wright is the accepted scientific name for this species of Ruellia. It was named and described by Carlos (Charles) Wright in Flora Cubana in 1870.

The genus, Ruellia Plum. ex L., was described by Carl von Linnaeus in Species Plantarum in 1753 citing a previous description by Charles Plumier.

As of 11-5-22 when this page was last updated, Plants of the World Online lists 362 species in the Ruellia genus. Ruellia is a member of the plant family Acanthaceae with a total of 207 genera. Those numbers are likely to change as updates are made and are based on figures from Plants of the World Online by Kew. 

Distribution map of Ruellia simplex from Plants of the World Online. Facilitated by the Royal Botanic Gardens, Kew. Published on the Internet; Retrieved on August 3, 2021.

The above distribution map for Ruellia simplex is from Plants of the World Online. Areas in green are where the species is native and purple where it has been introduced.

The map on iNaturalist shows where members have made observations. Anyone can join and it is a great website to confirm and share your observations. The maps on iNaturalist are continually updated as members post new observations. 


Ruellia simplex on 6-2-12, #95-36.

My Ruellia simplex (Mexican Petunia) was given to me by my good friend and fellow plant collector, Walley Morse, of Greenville Mississippi. He brought me a nice pot full in the fall of 2011. I kept them inside in the sunroom over the winter then transplanted them along the wall next to the east sunroom. I decided that the area was too shady, so I moved them to the bed next to the west sunroom.

Ruellia simplex at 36″ tall on 7-2-12, #106-23.

I planted them in several spots and they did very well.

Family: Acanthaceae
Origin: Mexico, South America, and the Caribbean
Zones: USDA Zones 8a-11 (10 to 40° F)
Size: 36-48” tall
Light: Sun to part shade
Soil: Average to moist, well-drained soil.
Water: Average to wet.
Notes: Can be used as a marginal water plant.

Ruellia simplex flower on 7-7-12, #109-5.

I really like their very dark green, lance-shaped leaves with kind of a corrugated look. They can produce blue, purple, pink, or white flowers. Unfortunately, the only thing I didn’t like about mine was their pink flowers. I guess when Walley found his start he didn’t have a choice.

<<<<2013 IN MISSOURI>>>>

Ruellia simplex in the bed on the south side of the house on 5-21-13, #149-9.

I sold the mansion in Mississippi and moved back to the family farm in mid-Missouri in February 2013. I gave up around 200 potted plants but brought quite a few with me, including all of the Mexican Petunia.

I planted two of the pots in the bed on the south side of the house. One on each side of the downspout on the southwest corner.

Ruellia simplex in front of the chicken house on 6-1-13, #151-61.

I planted the third pot in front of the chicken house…

The Ruellia simplex is native to Mexico, South America, and the Caribbean. They are perennial in USDA Zones 8a-11 and Florida has listed them as an invasive species.

Ruellia simplex in the south bed on 6-6-11, #155-24.

The Ruellia simplex is not very particular about their soil. Although they will do well in average, well-drained soil, they also do fine in wet soil. Well-established plants also have a moderate amount of drought tolerance.

Ruellia simplex in the sough bed on 7-30-13, #165-53.

They will grow in sun to part shade but produce more flowers in full sun. After they flower you can cut the plant back to encourage them to flower again.

Ruellia simplex in the south bed on 8-8-13, #171-24.

Ruellia simplex can spread aggressively by underground rhizomes and from self-seeding. If it likes you and its conditions, be prepared…

Ruellia simplex in front of the chicken house on 9-17-13, #188-51.


Ruellia simplex in the south bed on 9-17-13, #188-52.

The plants on the right and left of the Mexican petunia are Talinum paniculatum (Jewels of Opar) which were also given to me by Walley Morse.

Ruellia simplex on 10-25-13, #198-24.

I knew it would happen sooner or later but I wasn’t sure when. I had been away from here for many years. Mississippi didn’t get a frost until December, so October 25, 2013, was like a shock!

Ruellia simplex in the shed on 10-25-13, #198-25.

I was somewhat prepared, though… Knowing the Ruellia simplex wasn’t cold-hardy here, USDA zone 6, I had already dug several pots and put them in the shed. I left the one clump in the south bed to see what would happen. Umm… I am writing this page on March 14, 2018, and I am a bit confused… I thought I brought three pots from Mississippi and there seem to be four or five pots in this photo. Hmmm…  Maybe some of the clumps were too big for one pot.

Anyway, after a while, I moved these pots to the basement. They didn’t like that too well either.

Ruellia simplex in the south bed on 12-7-13, #208-55.



Ruellia simplex in the south bed on 6-1-14, #228-67.

It seems I learned a valuable lesson with the Mexican Petunia. The clumps I dug didn’t make it and I was surprised the clump I didn’tdig up did. It did very well through the summer of 2014 but didn’t return in the spring of 2015.


Ruellia simplex from Mrs. Wagler on September 9, 2018, #505-28.

When I took a few excess plants to Wagler’s Greenhouse on September 9, 2018, we were talking about plants and somehow the subject about Mexican Petunias came up. She said she had a few that she had had for a while. I told her I had brought some back from Mississippi but they didn’t work out here. I asked her what color the flowers on hers were and she said blue. She asked if I wanted a start, and of course, I said yes. She went to the bed where hers were, went inside and got a shovel, and proceeded to dig a few of the newer offsets. Their roots go pretty deep but she manages to get some that had a few roots. It was funny how she was digging with the shovel barefooted (she is Amish and women and children are pretty much always barefooted).

I brought them home and put all the three offsets she gave me in the same pot. It was September 9 already and I didn’t think they would make it through the winter in the ground. Since I had overwintered the plants Walley had given me inside in 2011, I figured they would here as well.

Ruellia simplex on 10-10-18, #519-60.

Still looking good on October 10, 2019. That was the day I moved all the potted plants into the house because an “F” was in the forecast.


Ruellia simplex on 2-17-19, #548-5.

The Ruellia simplex did just fine in my bedroom over the winter waiting for spring so it could be in the ground outside.

Ruellia simplex (Mexican Petunia) on 5-25-19, #576-67.

When temperatures permitted, I planted the Ruellia simplex along the right side of the porch in the north bed. They are doing fine, but a few of the plants want to lean so I didn’t get them all in this photo.

Ruellia simplex (Mexican Petunia) on 7-4-19, #598-14.

Looks like a hungry grasshopper stopped by for lunch…

Ruellia simplex (Mexican Petunia) on 8-11-19, #613-34.

A very interesting point I must make… The leaves on the Ruellia simplex Mrs. Waglar gave me are much larger than the plants from Mississippi. Nor are these leaves “puckered”.

Ruellia simplex (Mexican Petunia) on 8-11-19, #613-35.

I have seen a few buds but no flowers…

Ruellia simplex leaf on 8-11-19, #613-36.

These leaves are very long for sure…

Ruellia simplex (Mexican Petunia) on 8-20-19, #615-17.

I decided to put a few rocks against the stems to hold them up.

Ruellia simplex (Mexican Petunia) on 8-20-19, #615-18.

Even without flowers, Ruellia simplex is one of my favorite perennials. I really their dark green lance,-shaped leaves.

Ruellia simplex (Mexican Petunia) on 8-20-19, #615-19.

As you can see, if you compare these leaves with the plants from Mississippi, there is no puckering…

Ruellia simplex (Mexican Petunia) on 8-30-19, #618-48.


Ruellia simplex (Mexican Petunia) on 8-30-19, #618-49.

I am not sure what keeps happening with the buds. It seems like I see them but then they disappear…

Ruellia simplex (Mexican Petunia) on 9-6-19, #624-12.

I know I sometimes get a little carried away with photos… But, as long as we are here, the Lysimachia nummularia ‘Goldilocks’ have spread very well this past summer. I also planted a Colocasia ‘Coffee Cups’ which has also done very well.

Ruellia simplex (Mexican Petunia) flower on 9-6-19, #624-13.

Ahhh… Finally flowers. Such a nice color compared to pink… The flowers are also much larger than the plants from Mississippi. Hmmm…

Ruellia simplex (Mexican Petunia) on 9-6-19, #624-14.

It is very interesting growing these plants from Mrs. Wagler. It makes me wonder a few things because of the differences from the Mississippi plants. Larger and longer leaves with no puckering and larger flowers are the main differences. Not to mention Mrs. Wagler has had hers for several years in zone 6 and Ruellia simplex aren’t supposed to be hardy above 8 (7 with mulch).

Ruellia simplex (Mexican Petunia) on 9-6-19, #624-15.

There are a lot of buds so more flowers are on the way.

Ruellia simplex (Mexican Petunia) on 10-1-19, #637-6.

In the south, Ruellia simplex is considered very invasive, which I have witnessed first hand. That is not a problem here. The trick is to get them to survive the winter. I put them on the north side in this particular location because the south side is more open and gets a lot of wind. Even so, when it warms up and freezes off and on over the winter it is not good for some perennials either.

Ruellia simplex (Mexican Petunia) on 10-1-19, #637-7.

Mexican Petunia can be overwintered inside as stem cuttings or by digging a few offsets like Mrs. Wagler did. I had been thinking I should do that, and planned to, but failed to do so…

Ruellia simplex (Mexican Petunia) at 47″ tall on 10-11-19, #639-83.

I had to move the potted plants inside for the winter on October 11 because an “F” was in the forecast for that night. While I should have either taken cuttings or dug a few offsets, or both, I only took photos…

Unfortunately, the Ruellia simplex didn’t return in 2020. I should see if Mrs. Wagler a few more I could possibly get…

I hope you enjoyed this page and maybe found it useful. If you have any comments, questions or suggestions, I would like to hear from you. Please click on “like” if you visited this page. It helps us bloggers stay motivated. 🙂 You can check out the links below for further reading. The links take you directly to the genus and species of this plant.


NOTE: The data (figures, maps, accepted names, etc.) may not match on these websites. It depends on when and how they make updates and when their sources make updates. Some websites have hundreds and even many thousands of species to keep up with. Accepted scientific names change periodically and it can be hard to keep with as well. Some of the links may use a name that is a synonym on other sites. In my opinion, Plants of the World Online by Kew is the most reliable and up-to-date plant database and they make updates on a regular basis. I make updates “at least” once a year and when I write new pages or add new photos but I do get behind. We are all a work in progress. 🙂


4 comments on “Ruellia simplex (Mexican Petunia)

  1. Jerusa Monteiro de Oliveira says:

    Gostei do post. Parabéns! Ganhei um galho dessa espécie roxa. Coloquei na água por 1 semana para enraizar. Já transferi pro vaso tem um tempo. Aguardando a floração.

    Liked by 1 person

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