This post was updated on June 18, 2023
Many people consider beardtongue or penstemon, sometimes called foxglove beard-tongue, a wildflower best left to native settings rather than featured in a suburban flowerbed. That’s because in its native forms, the petite flowers and slim profile doesn’t draw immediate attention.
Striking hybrids are starting to change that. Let’s take a closer look.
Adventurous gardeners have discovered beardtongue works well in many situations beyond native plantings. While there are roughly 250 native North American species and dozens of cultivars, they all bear racemes of snapdragon-like flowers on upright stems above attractive basal foliage. Penstemons bring airiness and textural interest to companions like lilies, bellflowers, salvias and so much more.
The best hybrids for Pennsylvania’s climate derive from penstemon digitalis or smooth beardtongue, which is native from eastern Canada to the Southeastern US. This species can reach five feet tall but its cultivars top out at 24 to 30 inches.
Add to these many shorter, bushier introductions created from western species in a wide range of colors and you’ve got a strategy for success no matter where you live.
Why Plant Beardtongue
Beardtongue makes an excellent “filler” for a multitude of garden scenarios. It’s invaluable for contributing dainty detail in late May and June, for adding substance to rock gardens, for setting off boulders and softening hardscape edges. The basal foliage stays neat and tidy all season long.
A perfect choice for mixed borders and pots, penstemon comes in a wide range of colors and sizes. Whether tall or short, penstemons are always graceful to behold and they never need staking.
Two must-have cultivars
Two easy to find, proven performers are Husker Red and Dark Towers. Husker Red has been around for years but Dark Towers is a more recent introduction with richer coloring. Both reach 24 to 30 inches tall in bloom and survive our harsh winters better than most. They simply light up the garden with their twinkling, starry florets.
Of the two, I find Husker Red to be more vigorous. But Dark Towers blooms longer. Its foliage retains deep coloring all summer, whereas Husker Red turns olive-bronze by midspring. Both are improved versions of smooth penstemon, so they’re well adapted to our humid summers. Even so, penstemons rarely last more than a few years even under the best of conditions. But they’re so worth it!
Husker Red – Cream-colored buds open white with a pale lavender wash atop handsome red-flushed foliage. (The name Red refers to the foliage, not flower color.) Dark threads in the flower petals guide pollinators. Hummingbirds like to visit this plant, too.
Dark Towers – Magenta-based pale buds open lavender-pink with white tips atop clean foliage that stays dark. The two cultivars look nearly identical except for the intensity of coloring.
Cultivars bred from western species come in brighter colors, ranging from hot red to intense blues, purples, pinks and bicolors. Because their parentage comes from higher and drier altitudes, they are often short-lived in Pennsylvania. If you’ve tried these in the past and they didn’t last more than a season or two, this could be why.
A new western hybrid for me this year is Red Rocks (which is pink) from High Country Gardens. It’s blooming for the first time at 15″ tall. Foliage is glossy green. I love the hot pink blooms against a companion planting of silvery cerastium (snow-in-summer) in my front rock garden. It should bloom all summer.
Update June 2023 — Red Rocks is proving to be an outstanding cultivar. After 3 years it is cold-hardy, blooms off and on for long periods all summer, and bumblebees adore it. The habit is neat and tidy, never exceeding 18″ tall and 8 to 10″ wide. Multiple stems per plant are just covered in bells the entire length. Allowing at least one-third of the plant to remain in place helps with survival during wet winters. Outstanding!
Tempting new varieties are coming out of the trade all the time. Here’s one at the top of my wish list: Dakota Burgundy. With near-black foliage and rich pink flowers, this beardtongue is a head-turner. Claiming good hardiness to zone 5, it should do fine in Pennsylvania. I will certainly have to try it!
Update Fall 2023 – I planted Dakota Burgundy plugs in spring and since then, the plants tripled in size with only modest flower output (one or two small stems per plant) the first year. Foliage is dark and attractive. I’m anxious to see their floral display in spring 2024!
Blackbeard is similar, also with dark foliage and pink flowers.
Other hybrids of note for their exceptional color:
Margarita BOP has electric blue-violet flowers shaped like snapdragons (they’re in the same family). It has a short (about 15″) airy habit, so keep it paired with low companions or mass it for best visibility. The color is truly eye-popping. Bloom time is late spring.
Red Riding Hood is an intense red. No worries about this one getting lost; it will be calling you from across the yard! If you want a slightly cooler red, try Quartz Red.
These are by no means your only choices. There are bicolor pinks, purples, even a yellow on the market now. Some are only half-hardy, so be sure to check for height and zone information when purchasing. Hybrids vary considerably in size and performance.
A general rule of thumb is that brightly colored penstemons are not known for longevity. If they only last a season or two, it’s nothing you’re doing wrong. These plants simply prefer drier conditions than we can give them. If you’re in zone 6 and just starting out with beardtongue, I strongly recommend Husker Red or Dark Towers first, then branch out (sorry) from there. Or simply enjoy the others as annuals.
Siting and Care
Penstemons will do fine in any soil except very acidic as long as it’s well drained. Even hybrids cannot tolerate soggy spots. If you use a shredded wood mulch, keep it away from the stem. A pea gravel is helpful here. So is siting penstemons on slopes, in raised beds or rock gardens where good drainage is guaranteed.
You’ll want to cut off the flower stalks to neaten the foliage after bloom. These plants won’t spread much. Disease and pest resistance is average to excellent. The basal rosette stays tidy all year and is nearly evergreen, dying only after a sustained freeze.
Besides good drainage, the newer hybrids benefit from fertile soil, adequate watering during dry spells and plenty of sun. None need staking. A light dressing of fertilizer in spring is optional.
I’ve only grown Husker Red, Dark Towers, and now Red Rocks, so I can’t vouch for other hybrids’ survivability. But all the cultivars listed here are hardy in zone 6 or lower, so they’re all worth trying.
If you have a shady border or woodland edge rather than sun, you can grow Penstemon calycosus, sometimes called Longsepal or Calico Penstemon. (Available by mail order if you can’t locate it locally.) It’s a pretty lavender-white woodland penstemon that thrives in part shade. Being native, it’s taller at 2 to 4 feet high, and quite attractive.
With any penstemon variety, you can always take cuttings and propagate your own plants. I don’t because I have neither the space nor the light to grow seedlings. But if you’ve got the right conditions, why not try it? Otherwise, enjoy penstemons in situ, while they thrive. You should get several years out of them at least.
You can either mass beardtongue in groups or tuck between your other plants. They’re perfect for bulking up sparse sunny borders, adding a frothy counterpoint to more substantial plants, and filling the gap between spring bulbs and the main show. The more petite cultivars even look great in pots. A useful plant indeed!
