There are three Rs for lots of things but when it comes to Oklahoma wildflowers the three Rs stand for Ratbidia, Ruellia and Rudebeckia. (Say that fast three times!) I had to do a quick check before beginning this column for many “wildflowers” are simply weeds in bloom. I checked three books on weeds and none of them contained the three Rs, so here we go…

Most everyone knows Rudebeckia; so popular is this genus in perennial gardening we forget it is a wildflower in much of North America. Hybrids come from three primary genuses, R. hirta, R. fulgida and R. lacinata; these prairie natives are better known as Black-Eyed Susan, Yellow coneflower or their varietal names ‘Irish Eyes’, ‘Indian Summer’ or ‘Goldsturm’.

Technically this yellow daisy flower with a dark brown, cone-shaped center that blooms the roadsides in late summer is a biennial. Rudebeckia hirta, grows a clump of rough, hairy and often blooms the first year breaking all the biennial rules for biennial flowers. It’s beautiful though, as well as deer and drought resistant.

Ratbidia is a prairie wildflower, bloom of species R. pinnata looks very similar to the Black-eyed Susan except the petals are less stiff and the brown disc taller like a large blackberry standing on end. The Ratbidia I am excited about though is commonly known as Mexican hat. R. columnaris (aka columnifera) has a smaller flower with yellow or red-brown petals and a central disc that stands tall like the center crown of a Mexican sombrero. The plant’s stems are quite wiry with small deeply divided leaves. In its early growth it most definitely can be mistaken for a weed. It’s a plant that loves the heat though and adds “filler flowers” to a perennial border.

Ruellia is the last of this week’s highlighted wildflowers. I had no idea it grew wild in these parts until I purchased a home with a meadow! In the nursery, Ruellia is sold as Mexican petunia, (R. brittoniana) and grows in Oklahoma as an herbaceous perennial; with dark purple flowers and willow-like foliage, it dies back to the ground each winter. The species native to the central U.S. (the humble R. humilis) however is shorter, has soft, rounded leaves and pale, lavender flowers from late spring to fall. I see no reason this would not be a great garden addition. It has bloomed for months on Mother Nature’s watering schedule amidst the grass and prairie clovers. Email me if you would like for me to save you some seed.

LeeAnn Barton has worked with nurseries for more than 20 years. She digs in the dirt in Stillwater. Direct any questions to her, especially about tree selection, by emailing