This is Penstemon cobaea, the largest flowered of all the penstemons. According to Pennell in Scrophulariaceae of Eastern Temperate North America (which everyone not paid by the word refers to as SETNA), Nuttall, in his journey to “the Arkansas Territory”, found this species growing along the Red River in present-day Choctaw County in Oklahoma in late May and early June of 1819. So, 193 years ago, maybe on this day, Nuttall collected his first specimen of this species.
Discovery of this species led to hybridization with the monsoonal species from the highlands of Mexico being brought back to Europe about the same time; the large-flowered or “bedding” penstemons were the result. (These are semi-hardy here if I water the daylights out of them after mid-July…my own private monsoon….so that the plants produce basal leaves that allow them to overwinter; it’s hardly worth the trouble.)
Pennell described the habitat as “black or red loam, usually calcareous, Nebraska to Texas. Prairies from the Platte River of eastern Nebraska to the Colorado River in central Texas; in post-oak woods of the Coastal Plain of Texas from the Red and Sabine Rivers to the Nueces River.”
Not having post-oak woods in my garden, I fake it by growing this close to the small pool I put in years ago, where water can wick up to the plants’ roots. (This is a fancy way of saying the pool is probably leaking.)
Penstemon cobaea is a short-lived plant here but reseeds a little, mostly finding prairie-style happiness right by the edge of the flagstone path, where the flowering stalks can be knocked over by dog tails. This is a really dumb place for a plant to grow, but they don’t listen to me. (If you think people don’t listen to you, try talking to plants and see what happens.)
There’s a spectacular white form, too.