Showy Beardongue

Penstemons are in the Plantain (Plantaginaceae) family. The word “penstemon” is derived from the Greek words ‘pente” meaning five and ‘stemon’ meaning stamen. Of course this refers to the 5 stamens of Penstemon flowers.

The common name of Showy beardtongue is absolutely fitting, but I prefer Purple beardtongue or Purple Ozark beardtongue. As is often the case, there are numerous other common names:

• Cobaea beardtongue
• Prairie Beardtongue
• Showy Beardtongue
• Purple Beardtongue
• Purple Ozark beardtongue
• Foxglove beardtongue
• Foxglove penstemon
• Large-flowered beardtongue
• Wild foxglove
• Dew Flower

Purple beardtongue begins flowering in late April and continues through May. Occasionally, it also blooms in June and July.

These large, tubular flowers are typically deep purple. However, as you can see from the photos below, Purple beardtongue displays a range of shades, from dark purple to a reddish purple and even a very pale purple. Some of the most striking flowers have a variation of a paler color on the face, while the rest of the flower remains dark purple.

Penstemon cobaea is a short-lived perennial that reseeds readily in a suitable habitat. In spring, its basal rosette is easily recognizable by its glossy, toothed leaves. This is an ideal time to transplant young plants.

The stem leaves of Penstemon cobaea are opposite and sessile, with serrated edges and a beautiful waxy sheen.

The stem, buds, calyces and flowers are densely pubescent.

The filaments of the four stamens resemble ribs, supporting the open flower and creating an inviting space for bees to crawl inside. Dark anthers holding the pollen can dangle at the end of the filaments. The whitish style is centered in front of the stamens. A fifth sterile stamen (staminolde) protrudes from the flower’s mouth like a small brush.

The plant stands tall at a little over two feet. A single plant can have multiple stems and many flowers. Occasionally, stems heavy with flowers lean on other plants or flop to the ground, especially after a storm. However, they still put on a beautiful show, and if left alone, the flowers will grow upright. I’ve never felt the need to stake them in the garden.

Large bees such as Bumblebees are the primary pollinators of Penstemon cobaea. Other visitors include hummingbirds, metallic green sweat bees, large carpenter bees, moths and other fascinating insects.

It's fascinating to observe Bumblebees crawling deep within the corolla until nothing is visible but their hind legs! As they maneuver into the flower, they inadvertently pass by the stigma, depositing pollen grains from previous visits, hence pollinating this flower. To reach their target, the nectary, they wiggle deep inside the flower, passing over the pollen-covered stamens. As they back out of the flower, new pollen grains are dusted over their hair once more, preparing them for pollinating the next flower.

The video below shows an American Bumblebee (Bombus pensylvanicus) climbing inside a flower, backing out, and then flying into another.

This video captures a Brown-belted Bumblebee (Bombus griseocollis) as it visits the flowers. Although not as large as the American Bumblebee, this bee remains an effective pollinator of Penstemon cobaea. I’ve also observed Two-spotted Bumblebees (Bombus bimaculatus) and Common Eastern Bumblebees (Bombus impatiens) crawling into the flowers to pollinate them.

Large carpenter bees (Xylocopa virginica) have a unique way of accessing nectar. They obtain nectar by piercing the corolla at its base rather than climbing inside. In doing this, they bypass the pollen covered anthers and don't pollinate the flower.

Penstemon cobaea thrives in rocky, limestone, or dolomite glades and other dry, open, sunny areas. It is one of the most beautiful native plants to add to a sunny spot in a wildflower or any flower garden. Starting from seed is easy, and under the right conditions, it blooms the second year. It's also available at many native plant nurseries.

Below are a couple of photos showcasing Penstemon cobaea in one of its natural habitats, a limestone glade.

Penstemon cobaea is native to 11 states. Natureserve lists it as Critically Imperiled in 2 states- Colorada and Iowa. It's listed as Vulnerable in Arkansas and Nebraska, and Apparently Secure in Oklahoma. All other states show no status on Natureserve.

In Arkansas, Penstemon cobaea,has a Conservation Value of 10 in the group of 8-10. “Conservative taxa with strong fidelity to intact habitats. These taxa tend to exhibit late-successional characteristics like long lifespans with low seed sets and an inability for far ranging dispersal.”

Like many native wildflowers, Penstemon Cobaea plays an important role supporting many insects. While it is mostly pollinated by large bumblebees, it is also visited by smaller bees, butterflies, moths and other interesting insects as well as hummingbirds. It is a host plant for the Dotted Checkerspot butterfly.

If deer are a problem in your garden, this is a great plant to add as it is deer resistant. In fact, rabbits also avoid the mature plants, however they may nibble on tender, young transplants.