Penstemon

Botanical/Latin
   Penstemon

Pronunciation
   Pen-stay-mon

Common Name
   Beard Tongue

Hardiness zone range
   3 - 8

General Comments
Delightful perennials with evergreen and semi-evergreen foliage that produce upright spikes of small, foxglove-like, tubular flowers in shades of white, pink, red, lavender, and purple. Most flower in late spring and summer, and some will repeat in late summer and autumn if trimmed back after flowering.

Uses
They make wonderful plants in well drained beds and borders; the upright spikes create height and structure to low plantings, and provide a valuable continuity of color and interest. Ideal locations would include raised beds, sunny sloping banks, rockeries, or at the base of sunny walls.

Hummingbirds like to visit the tubular flowers which make good cut flowers.

Light Preference
Full sun

Culture
The most important factor is well drained conditions. They grow best in light, gravelly or sandy soils that do not become wet and saturated in winter. At planting time, it is important to select the site carefully, and, if in doubt, amend the soil with extra grit or gravel to ensure good drainage.

After flowering, the spent flower stalks should be sheared back to the basal rosette of foliage; this encourages re-growth and renewed flowering. Clumps should be lifted and divided every 3-4 years.

Background
The botanical name comes from the Greek words Pente (five) and Stemon (stamen); this refers to the unusual flower configuration of having five stamens (male parts). There are over 200 different species of Penstemon. All but a few are native to North America, and most of these are from the high mountainous areas where the drainage is sharp and during the winter they are covered by insulating layer of snow (see Splendor Suggestions). The genus was first recognized in 1762. From 1814 onwards, many species were collected by intrepid plant hunters who found and introduced them to cultivation. Some of the best known were collectors like David Douglas (P. confertus, diffusus, ovatus, venustus etc), a "wily" Scot, who before his untimely death in Hawaii, (where he was gored by a bull in a pit dug by natives) had spent most of his life collecting and sending plants back to Britain from Western States. Thomas Nuttall (P.cobaea,digitalis, humilis etc.) was an Englishman who became the curator of the Botanic Gardens at Harvard University, and after many expeditions finally managed to cross the Rockies. Professor Asa Gray (P.barrettae, laetus, linarioides etc.) was the distinguished professor of Natural History at Harvard. He became one of the founding fathers of the Arnold arboretum, and co-authored with John Torrey, (another collector of Penstemons), The Flora of North America. Some of these fine species were hybridized to enhance the ornamental characteristics, the hardiness, and their ease of culture. This continues today. We offer a selection of the ones we have found to be the most adaptable and reliable in our eastern gardening zones.

Splendor Suggestions
Some of the most beautiful Penstemon species hail from high mountainous regions where they are protected from desiccative winds by an early and long lasting layer of snow. As mentioned earlier, good drainage is vitally important, but also consider protecting the rosette of evergreen foliage. This can be done by placing some evergreen boughs over them in late autumn, or laying an insulating layer of mulch around the base of each clump. Another alternative is to use modern, fleece-like, frost blanket materials supported by a low wig-wam of wire or bamboo canes. The advantage of this method is that air can move, allowing good ventilation while protecting the foliage.

Companion Plants
They combine well with Lavandulas, Dianthus, Echinops, and silvery grasses like Festuca `Glauca' or Helictotrichon. Try them also with the flat heads of Achillea; the soft pink and white shades of A. `Apple blossom' and `Snowsport' make good color combinations. In mixed plantings, they go nicely with Buddleias - especially the blue, mauve, purple, and white shades- and Vitex .