Wild Petunia, Fringeleaf Wild Petunia, Hairy Ruellia, Low Wild Petunia, Prarie Petunia
Synonyms of Ruellia humilis (14) ) (Updated on 8-3-21 from Plants of the World Online): Dipteracanthus ciliosus var. parviflorus Nees, Gymnacanthus humilis (Nutt.) Oerst., Ruellia caroliniensis var. parviflora (Nees) S.F.Blake, Ruellia ciliosa var. humilis (Nutt.) Britton, Ruellia ciliosa var. longiflora A.Gray, Ruellia ciliosa var. parviflora (Nees) Britton, Ruellia humilis f. alba (Steyerm.) Fernald, Ruellia humilis var. calvescens Fernald, Ruellia humilis var. depauperata Tharp & F.A.Barkley, Ruellia humilis var. expansa Fernald, Ruellia humilis var. frondosa Fernald, Ruellia humilis f. grisea Fernald, Ruellia humilis var. longiflora (A.Gray) Fernald, Ruellia humilis var. typica Fernald
Ruellia humilis Nutt. is the correct and accepted scientific name for the Wild Petunia. It was named and described by Thomas Nuttall in Transactions of the American Philosophical Society in 1835.
The genus, Ruellia Plum. ex L. was described as such by Carl von Linnaeus in the second volume of the first edition of Species Plantarum in 1753. He cited Charles Plumier in his descriptions and possibly named the genus.
Plants of the World by Kew lists 360 species in the Ruellia genus (as of 8-3-21 when this page was last updated). It is a member of the plant family Acanthaceae with 206 genera. Those numbers could change as updates are made by POWO.
The above distribution map for the Ruellia humilis is from the Plants of the World Online. Areas in green are where the species is native and purple where it has been introduced. The map on the USDA Plants Database for North America (above Mexico) is similar but doesn’t include Nw York.
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 make new observations.
THERE ARE SEVERAL LINKS AT THE BOTTOM OF THE PAGE FOR FURTHER READING AND TO HELP WITH A BETTER POSITIVE ID.
I first noticed many Ruellia humilis growing in the ditch in front of the house when I moved back to the family farm in 2013. They are scattered throughout the north side of the main pasture/hayfield but not in large colonies. They just kind of grow as single plants. Ruellia humilis is a variable species as far as its hairiness, leaf type, and corolla size are concerned. Missouri Plants lists three species of Ruellia in Missouri but so far this species is the only one I have found.
Ruellia humilis on 9-8-18, #504-37.Ruellia humilis is a perennial plant that grows to around 12” tall from a fibrous root system. They can either have single or multiple stems from the base.
The leaves grow in an opposite fashion along the stems and can have short petioles (leaf stems) or may be sessile (no petioles). The shape of the leaves is quite variable and is said to be narrowly to broadly ovate, broadly lanceolate, deltoid, or ovate. Leaves are usually up to 2 1/2 long x 1” wide and are pointed to rounded at the tip and angled to rounded at the base. The upper and lower surfaces are hairy.
Descriptions of the flowers on some websites, such as Missouri Plants, can get quite technical. The short version, in layman’s terms, is that the flowers can be light lavender to light purple, have five petals corollas), are funneled-shaped, and have no floral scent. There are darker purplish lines that serve as “nectar guides” for insects.
The above photo, although blurry, show the long floral tube. I need to take better photos…
Flowers open in the morning and fall off in the evening. They are easily recognized as petunias. When I first noticed this species growing in the ditch along the road in front of the house, I thought “that looks like a petunia.” Although they look similar enough to the Petunias grown in planters, they are actually in different plant families…
In the above photo, you can see they can branch out somewhat. Ruellia humilis can be found in a variety of habitats and is not really particular about the soil type. In more fertile soil, they tend to grow scattered as single plants rather than in large colonies. They tend to like somewhat drier soil and cannot compete well with taller plants where the soil is moist. The Ruellia humilis is a neat plant that I should take more photos of…
I have enjoyed photographing and learning about the many wildflowers growing on the farm and other areas. My farm is in Windsor, Missouri in Pettis County (Henry County is across the street and Benton and Johnson aren’t far away). I have grown over 500 different plants and identified over 100 species of wildflowers (most have pages listed on the right side of the page). I am not an expert, botanist, or horticulturalist. I just like growing, photographing, and writing about my experience. I rely on several websites for ID and a few horticulturalists I contact if I cannot figure them out. Wildflowers can be somewhat variable from location to location, so sometimes it gets a bit confusing. If you see I have made an error, please let me know so I can correct what I have written.
I hope you found this page useful and be sure to check the links below for more information. They were written by experts and provide much more information. Some sites may not be up-to-date but they are always a work in progress. If you can, I would appreciate it if you would click on the “Like” below and leave a comment. It helps us bloggers stay motivated. You can also send an email to me at firstname.lastname@example.org. I would enjoy hearing from you especially if you notice something is a bit whacky.
FOR FURTHER READING:
PLANTS OF THE WORLD ONLINE (GENUS/SPECIES)
INTERNATIONAL PLANT NAMES INDEX (GENUS/SPECIES)
WORLD FLORA ONLINE (GENUS/SPECIES)
USDA PLANTS DATABASE
U.S. FOREST SERVICE
MISSOURI BOTANICAL GARDEN
KANSAS WILDFLOWERS AND GRASSES
KANSAS NATIVE PLANTS
LADY BIRD JOHNSON WILDFLOWER CENTER
FRIENDS OF THE WILDFLOWER GARDEN
MARYLAND BIODIVERSITY PROJECT
MICHIGAN STATE UNIVERSITY
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 (and if they update their sources or even read what they say). Well, I can’t complain because I don’t always read all the information I have linked to. 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. 🙂