Fringeleaf Wild Petunia (Ruellia humulis)

Wild petunia flowers. Photo: G.D. Bebeau.

Paw Paw flower-Missouri Botanical Garden

The entire plant of wild petunia is hairy. Photo: Missouri Botanical Garden.

Ruelia humilis-Janice Lynn
Flower buds of Ruellia humilis. Photo: Janice Lynn.
By Joseph Mooney
This week’s native plant is wild petuniua, Ruellia humilis.
In the world of native plants, simplicity can be its own reward. That’s true for our native wild petunia, also called fringeleaf wild petunia or prairie petunia. It has none of the trappings of the decked out, over-the-top petunias, beautiful as they are, that you see every spring in the nurseries.
In fact, while it’s called wild petunia, Ruellia humilis is in the Acanthus family, most of whose members are tropical. The more well-known and ubiquitous annual garden petunia belongs to the tomato family (Solonaceae).
Ruella flowers-Missouri Botanical Garden

Wild petunia flowers. Photo: Missouri Botanical Garden.

Dried flower head of wild-petunia-Lurie-Garden

A close up of the spent flower head of wild petunia. Photo: Lurie Garden.


Wild petunia is a larval host plant for the common buckeye butterfly. Photo: Carolyn Cavender Alexander.

Hardy to zones 4-8, wild petunia is a perennial that’s native to eastern and central U.S. It’s happy in average to dry soils in prairies, meadows, and open woods and does well in full sun to part shade. Wild petunia grows to about 1.5 to 2 feet tall. The soft lavender to pinkish flowers are from 1-3 inches long and display some distinct dark-purple pollinator guidelines in their throats. The flowers occur mostly in upper leaf axils. Garden bonus: wild petunia blooms from May through October. It attracts pollinators and is the larval host plant for the common buckeye butterfly.
R. humilis is generally rare where it is native. In Michigan the state status of wild petunia is threatened, which affords the plant legal protection. Please purchase your plants from reputable native plant nurseries.