Penstemons, sometimes called beardtongues, are a fascinating group of plants, little known to the average gardener. To wildflower lovers and gardeners alike, penstemons offer beauty unexcelled by any other wildflower. The genus Penstemon is one of the largest genera of wildflowers in the world, with about 270 species. All are native to North America and Central America. At least one species is found in each of the United States, with the sole exception of Hawaii. The greatest number of species are found in the intermountain region of the Southwest. Penstemons are members of the figwort family or Scrophulariaceae, which also includes snapdragons and foxgloves. Many penstemons have showy flower spikes similar to those well-known garden flowers, with large tubular corollas.
In the wild these flowers grow under all sorts of conditions, some in moist meadows of the East, some in dry rangelands of the West, some in alpine meadows or rock crevices. In the garden different species are used as tall border beauties, prostrate rock garden mats, or small evergreen shrubs. The flowers range in colors across almost the entire spectrum, with vivid reds and scarlets, rich rose, intense shades of blue and purple, and many intermediate shades of pink and lavender, often beautifully blended to white and cream. Yellow is an unusual color in penstemons, but it does occur in a few cases.
Most species bloom during May and June in the mid-latitudes of the United States, June in the northern states, July in Canada, and August and September in Mexico. Thus they fill a temporal gap in the bloom of the border between the great displays of spring and the beginning of the midsummer phloxes and daylilies. Many penstemons are also fine for flower arrangements, with a single spray often making a bouquet in itself.
More than a hundred species have been grown by members of the American Penstemon Society, from the most common to a few of the rarest. There are still a great many species that have not been grown at all, and others that have only briefly been in cultivation. Penstemons offer a large field for experimentation and discovery for those who like to explore and expand the range of possibilities for our gardens.