The Great Penstemon Experiment is returning some preliminary results. While there are penstemons native to every state except Hawaii, species from the eastern half of the country tend to be white or lavender — nice, but generally not brilliant. Out west, however, they’re much more eye-catching, with many blues and reds. I’ve started a number of these from seed and purchased a few plants, focusing on species said to be “easy” or “adaptable.” The following all survived a full year in Kansas and are blooming now.
Penstemon strictus, the “Rocky Mountain Beardtongue,” grows over a broad area from New Mexico to Wyoming. It’s one of the most commonly grown — I’ve spotted it in at least two other gardens in town — and one of the easiest.
Penstemon pinifolius, a bushy mat-former, is native to Arizona, New Mexico and Mexico, but is hardy almost anywhere, including New England and Scandinavia. The form I have, “Compactum,” is half the size of the species and has redder flowers.
Penstemon “Blue Lips” is a hybrid of two creeping species from Colorado, P. crandalii and P. linariodes v. coloradensis. It would look good spilling over a wall.
Penstemon mensarum, the “Grand Mesa Beardtongue” or “Tiger Beardtongue,” is native to western Colorado, but is easily grown elsewhere. This and P. “Blue Lips” were the first to bloom this year, followed a few days later by P. eatonii.
Penstemon eatonii, the “firecracker” penstemon, grows in arid areas of Utah, Arizona and the Mojave desert, but adapts well to milder climates.
The evergreen rosettes of P. mensarum and P. eatonii may need protection from bright winter sun during sub-zero weather. Otherwise these have all been easy and undemanding. They are probably worth trying anywhere with a relatively dry climate.
Two species with extra-large flowers are native to Kansas, P. cobaea and P. grandiflorus. As you would expect, they do quite well in Kansas gardens.
There are a few more that should bloom within the next few months, and with luck there will be a lot more next year.
Addendum: a couple more.
Penstemon azureus is from northern California and southern Oregon. The seedling planted in full sun was gone by midsummer last year, but the ones that got some shade during the day survived. It probably would do well in Kansas in a partially-shaded spot with a little extra water.
Penstemon barbatus is found from Mexico to Colorado. It’s one of the easiest of the western Penstemons. The flowers are usually red, but in the variety “Twizzle Blue” they are indeed blue. The color varies from plant to plant. The one pictured is the bluest; the others in the yard tend more toward violet. It blooms the first year from seed, a nice trait in a perennial.
Update: I go into more detail about growing Penstemons in Kansas here.