The hairy wild petunia, Ruellia humilis, usually blooms for me mainly in July, but this year it’s still going strong. The plant is actually no relation to its namesake, but the light-purple, 2-inch, trumpet-shaped flowers do resemble small delicate petunias. Each is short-lived, but the plant puts out a steady succession.

Green leaves and stems carry short, soft, pale fuzzy hairs, which stick straight out from the edges, resulting in one of the plant’s common names: “fringeleaf petunia.” Growing one to two feet high, the plant branches well, making an attractive, bushy mass. It thrives in any well-drained soil, in sun or part shade. Not a flashy plant, but dependable and charming.

A perennial wildflower, it ranges from Florida to Texas, up to southern Wisconsin and Michigan, throughout the Midwest prairies and into eastern states as far north as Pennsylvania. I’m off the map, but it loves my garden.

Originally I bought one, but now I consider it a weed. Seedlings pop up everywhere in my yard, except deep shade. The plant breaks off at the crown when I try to pull it, leaving roots that quickly sprout new top growth: I have to loosen roots with a shovel or trowel before pulling.

Could this plant become invasive? I hope not. I read it will root along prostrate stems, but I don’t see that in my garden. Since there are many natural varieties, all somewhat different ... perhaps mine won’t? The New England Wild Flower Society — very careful about what they introduce — sells plants and seeds. In Pennsylvania and Wisconsin, it’s not only rare but endangered.

At one time I thought it was a bother, but after my recent struggles to remove euonymus and lamiastrum; after learning how bad cypress spurge was right after I planted it ... ruellia just doesn’t seem so bad. It’s fun to see where it will appear next. When Ward hasn’t mowed in a week, one blooms in the middle of the lawn. It’s happy with grass, commonly found in meadows (grazing animals like it).

When one gets in the way I know I can get rid of it, and when I want one, I can go find one. It’s handy to fill in bare spots. Studying it today, I just thought where I want to put one. There’s room next to some perilla, whose deep red-purple leaves will emphasize the light purple ruellia flowers.

Photos by C.H. Clark:

1. Note the hairs sticking out from edges.
2. One that volunteered between pavers in the path.

• Plant profile for ruellia humilis - scroll down a little to see the map of the plant's range.
• Ruellia humilis page - on the Missouri Plants site.
• Ruellia - about the whole genus.