Plant Common Name
These are true New World wildflowers. Penstemons are found all over the North American continent from Alaska and the arctic regions of Canada southward though the United States and into Mexico and Central America. Most of the species are found from the western states to the south. This large genus has more than 270 species and many hundreds of hybrids and cultivars. In the wild they inhabit lots of areas including moist open woods, meadows, alpine and piedmont regions, dry rangelands and deserts. Their showy, tubular flowers often have a hairy, infertile stamen (male reproductive structure) that appears at the mouth of the flowers, hence the common name beardtongue.
Most penstemons are herbaceous perennials, though a few are semi-woody subshrubs. Some are fully evergreen while others are semi-evergreen or fully deciduous. They are usually bushy and clump forming though many alpine species are very low-growing and form mats of foliage. The leaves of all are simple and have opposite arrangement. Leaf shape, size and color are variable but most have linear, lance-shaped or rounded leaves of green, gray-green or blue-green.
It’s easy to see that Penstemon is a member of the snapdragon family, Scrophulariaceae. Its attractive tubular flowers are two-lipped and look very snapdragon-like. Tall, bushy species form upright branched or unbranched clusters of colorful flowers and prostrate species produce them in clusters along the stems. Each tubular or bell-shaped has an upper and lower lip. Flower color may be purple, violet-blue, red, pink, white or yellow. Cultivated forms come in even broader, more elaborate shades. Bees, hummingbirds, butterflies and other pollinators pollinate the blooms and dry, capsule fruits follow.
Matching garden grown Penstemon to the right growing area is important. Some grow very well in average garden conditions while others have specific growth requirements. Most garden grown beardtongue species require full sun and average to fertile soil with ample drainage. Many species are drought tolerant once established, especially western ones. Some types are tall and suitable for sunny perennial beds and borders. Others are low-growing and ideal for rock gardens and containers. Many Penstemon are relatively short-lived and will require replacement after a few years.
Some more pleasing garden worthy penstemons include Parry’s beardtongue (Penstemon parryi), a high desert species from the southwest with large, vibrant pink blooms. The equally drought tolerant pineneedle beardtongue (Penstemon pinifolius) has fine foliage and produces clouds of small, red tubular flowers that are loved by hummingbirds. Interesting hybrids, such as the purple-flowered Penstemon 'Sour Grapes', are vigorous and have extra large flowers.