Ruellia humulis (Wild Petunia)
|Also known as:||Fringe-leaf Ruellia, Prairie Petunia, Hairy Wild Petunia|
|Habitat:||sun; dry sandy or rocky soil; prairie, open woods, rocky slopes, bluffs|
|Bloom season:||June - August|
|Plant height:||8 to 24 inches|
|Wetland Indicator Status:||GP: FAC MW: FACU NCNE: FACU|
|MN county distribution (click map to enlarge):|
|National distribution (click map to enlarge):|
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1 to a few stalkless flowers in the upper leaf axils. Flowers are funnel-shaped, about 1 inch across and 1½ to 2½ inches long, lavender to pinkish or pale blue, with 5 widely spreading lobes and darker lines inside the throat. Inside the tube are 4 white to purplish stamens and a white to purplish style with a divided tip.
The tube is contracted one third to halfway down its length, becoming very slender, pale greenish and stalk-like. The calyx surrounding the base of the flower has 5 linear lobes about half as long as the constricted part of the tube, the lobes with long, spreading hairs around the edges.
Leaves and stems:
Leaves are 1 to 3 inches long and up to 1 inch wide, toothless, densely hairy, lance to nearly diamond-shaped, with a blunt point at the tip, and stalkless or nearly so. Attachment is opposite, with pairs at right angles to the pair above and below. Edges are somewhat wavy. Stems are erect, single or multiple from the base, few-branched, weakly 4-sided, green to purplish, and variously covered in long, spreading, white hairs.
An Endangered Species in 1984 but long thought extirpated from Minnesota, a new population of Wild Petunia was discovered at Afton State Park in Washington County in 2005. According to the DNR, the area where it was found was formerly pasture so it is unknown if this population is naturally occurring or introduced. Since the Afton population is still the only known occurrence in the state, it was designated a Special Concern species in 2013; that status may change if additional locations are found. It is currently listed as Endangered in Wisconsin. Wild Petunia is increasingly available in the native plant trade and does well in cultivation.
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Photos courtesy Peter M. Dziuk taken in his backyard garden in Ramsey County.
Have you seen this plant in Minnesota, or have any other comments about it?