Plant Preference/Growing Conditions:

Wild petunias thrive in full sunlight and partial/little shade. It grows best in semi-moist and well-drained soil, such as sandy soil. Although not preferred, they can tolerate dry sites.

Growth Habit/Description:

Growing from rhizomes, wild petunias are a type of herb and can grow to form clumps of stems and flowers that can range from 1-2 ft in diameter. Flowers that grow from these clumps are typically form in clusters and vaguely shaped like a funnel; each flower is about 1.5 inches across in diameter and are lilac or light blue in color. Their leaves are light to medium green, simple, and ovate shaped and lightly hairy. Each leaf is approximately 3/4 - 1 inch long and 1/2 inch wide. It generally grows at a moderate rate.

Bloom Season:

The blooming of the wild petunia begins in late spring and can continue up to early fall (May to September).

Fall and/or Winter Interest?

No. Although wild petunias are hardy flowers and can persist through winters, their flowers will die when temperatures fall under 32 degrees Fahrenheit and snow can easily bury these short plants. Additionally, because it only attracts butterflies, bees, and hummingbirds, there are usually no pollinators to be seen with these plants during the winter.

Host Plant for Caterpillars?

Yes. The wild petunia is a host plant for the common buckeye butterfly (Junonia coenia) caterpillars and the white peacock butterfly (Anartia jatrophae) caterpillars.

Other Known Ecological Value?

Yes. Other pollinators are attracted to this flower, including hummingbirds, bumble bees (Bombus), carpenter bees (Xylocopa), sweat bees (Halictidae), and mason bees (Osmia). Because so many pollinators rely on the wild petunia as a source of nutrients, it supports the biodiversity of pollinators in it's native areas.

Origin of Name:  The wild petunia is very similar to the common garden petunia in physical appearance, but because this species of petunia is grown out in the wild, it's dubbed the wild petunia.

Related Plant Species:   The wild petunia is not actually related to petunias surprisingly, but one of it's relatives is the violet wild petunia (Ruellia nudiflora).

Use For Food/Medicine:

Plants in the Ruellia genus has been claimed to treat flu, asthma, fever, bronchitis, high blood pressure, eczema, and diabetes.

1. Plant database [Internet]. Lady Bird Johnson Wildflower Center - The University of Texas at Austin. [cited 2024 Sep 18]. Available from: https://www.wildflower.org/plants/result.php?id_plant=RUHU

2. Afzal K;Uzair M;Chaudhary BA;Ahmad A;Afzal S;Saadullah M; Genus ruellia: Pharmacological and phytochemical importance in ethnopharmacology [Internet]. Acta poloniae pharmaceutica. U.S. National Library of Medicine; [cited 2024 Sep 18]. Available from: https://pubmed.ncbi.nlm.nih.gov/26665388/#:~:text=The%20genus%20has%20been%20traditionally,pressure%2C%20eczema%2C%20and%20diabetes.

3. Plant database [Internet]. Lady Bird Johnson Wildflower Center - The University of Texas at Austin. [cited 2024 Sep 18]. Available from: https://www.wildflower.org/plants/result.php?id_plant=RUNU

4. U.S. Forest Service [Internet]. Forest Service Shield. [cited 2024 Sep 18]. Available from: https://www.fs.usda.gov/wildflowers/plant-of-the-week/ruellia_humilis_nutt.shtml

5. Wild petunia [Internet]. The Morton Arboretum. 2023 [cited 2024 Sep 18]. Available from: https://mortonarb.org/plant-and-protect/trees-and-plants/wild-petunia/#more-information

6. Wild petunia [Internet]. Ruellia humilis | Prairie Nursery. [cited 2024 Sep 18]. Available from: https://www.prairienursery.com/wild-petunia-ruellia-humilis.html#:~:text=Description-,Wild%20Petunia%20is%20a%20hummingbird%20favorite%20with%20trumpet%2Dshaped%20lavender,Peacock%20(Anartia%20jatrophae)%20butterfly.

7. Cottagegardennatives.com. [cited 2024 Sep 18]. Available from: https://www.cottagegardennatives.com/s/stories/native-plant-spotlight-fringeleaf-wild-petunia-ruellia-humilis-2

8. Petunia, wild, Ruellia humilis [Internet]. Leaves for Wildlife. [cited 2024 Sep 18]. Available from: https://www.leavesforwildlife.com/product-page/petunia-wild-ruellia

Last edited by Paola Sustaita, September 2024.