Penstemon is a large group of flowering herbaceous plants in the Plantaginaceae genus commonly known as beardtongue. There are over 275 varieties native to North and Central America and East Asia. These ornamental perennials are fairly short lived but very easy to grow and bloom in many different colors on stalks of varying heights. Among the most popular varieties are P. barbatus, P. campanulatus, and P. digitalis.
The flowers of this plant bloom in just about every color, in both pastel and bright shades, although yellows are rarely seen. The flowers are funnel shaped or tubular with a long, extended stamen, and grow up strong stalks. Plants in this species grow from a mere 4 inches (10 cm) to over 5 feet (1.5 m) tall and look quite similar to snapdragons, foxgloves, and gladiolas. The leaves can be lance shaped or rounded, with the larger leaves near the ground and smaller ones growing up the stalks.
These plants are a good choice for beginners because they are not picky about growing conditions and produce showy flowers. They will do best, however, in moist, humus rich soil that has good drainage. Penstemon will not survive in very wet conditions. Since their roots are quite shallow, a layer of winter mulch is required to prevent them from heaving out of frozen ground.
Penstemon can be easily grown from seed, though in most cases they will not produce flowers the first year. Impatient gardeners may be better off purchasing plants from a garden center for quicker blooming. These plants are often healthier and more disease resistant than those started from seed as well.
P. barbatus is probably the most familiar type of penstemon and is native to the southeastern United States. It grows from 2 to 3 feet (61 to 91 cm) tall and has egg shaped leaves. The flowers are about 1 inch (2.5 cm) long and are usually scarlet, although cultivars can be found in pink, orange, and white.
P. campanulatus is slightly different, with short, grassy leaves and purple, white, or violet flowers. It is native to Central America and is commonly known as harebell penstemon. This variety is less hardy than some others and will not tolerate very cold temperatures. It may survive winter with a thick, protective mulch.
P. digitalis, also called foxglove penstemon, grows wild in the central and eastern United States. Spikes of bell-shaped flowers may be pale pink, white, or red. This species does better in hot, humid climates than most and is winter hardy. It can grow up to 3 feet (91 cm) tall and has long, spiky leaves.
Some species of penstemon have been used as medicinal plants by Native Americans. Various tribes employed shrubby penstemon to treat everything from colds and headaches to scalp and skin problems. The root was also utilized for toothaches and placed directly on the affected tooth. It was even made into a decoction and used as an eyewash.
