Ruellia simplex C.Wright is the correct and accepted scientific name for this species of Ruellia. It was named and described by Carlos (Charles) Wright in Flora Cubana in 1870.
Ruellia brittoniana Leonard was named and described by Emery Clarence Leonard in the Journal of the Washington Academy of Sciences in 1941.
Plants of the World Online lists 249 accepted species in the Ruellia genus. It is a member of the Acanthaceae Family along with 183 other genera. (According to Plants of the World Online as of March 14, 2018, when I published this page.) Plants of the World Online is still uploading data so these numbers could change.
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. When I first did my research on the Mexican Petunia, most information online said they were Ruellia brittoniana. I discovered The Plant List when I moved back to Missouri and started the first Belmont Rooster blog in 2013. That website said Ruellia brittoniana was a synonym of Ruellia simplex. Most websites, other than plant databases, still use the name Ruellia brittoniana. The use of incorrect names by the industry and small businesses online is a real problem…
Doing scientific name research used to be difficult and frustrating. I would do an image search and find many different species that looked similar to my plants. Once I started using The Plant List to do name searches, many times I would find out all those names were synonyms of the same species. According to the 2013 version of The Plant List, there were 10 Ruellia species that are synonyms of Ruellia simplex. The Plant List is no longer maintained so I am now using Plants of the World Online by Kew.
Dave’s Garden is listing this species as Ruellia tweedyana but that species name is a synonym of Ruellia simplex. Dave’s Garden is pretty up-to-date, but sometimes… If you go to the link to Dave’s Garden at the bottom of the page, you need to scroll down to their comments. My experience with these plants in Mississippi was limited and they didn’t work out here in mid-Missouri. Most comments of people that have grown this plant would suggest against them because they are so aggressive.
I kept them inside in the sunroom over the winter then transplanted them along the wall next to the east sunroom. I decided that area may be to shady, so I moved them to the bed next to the west sunroom.
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.
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>>>>
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.
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.
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.
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 can spread aggressively by underground rhizomes and from self-seeding. If it likes you and its conditions, be prepared…
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.
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!
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 seems 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 to well either.
I don’t remember what happened with the Mexican petunia in the pots but there are no photos beyond the above photo. I know this plant did very well throughout the summer of 2014 but didn’t return in the spring of 2015. I was surprised it came up in 2014.
I would still like to do some experimenting with this species here or maybe a few of the cultivars. There are several… There is a trich to overwintering them here and I would like to figure it out. Well, one thing is for sure. It certainly isn’t invasive here. 🙂
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.