I spend a great deal of time observing structure as it occurs in nature, and attempt to replicate that in my desert garden. I have found that there are two common elements: first that plants tend to grow in asymmetrical patterns; and two, that they form the most interesting and striking colors and combinations.
Not a great lover of symmetry anyway, and being prone to create unusual mixtures of plants, I have created a number of interesting (at least to me) plant collages in my gardens.
The photo of penstemmon (penstemmon hirsutus) set against the Don Juan rose is a remarkable example of unusual color combinations.
Granted, Don Juan is a cultivar and the penstemmon (also known as beardtongue) is a wild plant, but their juxtaposition is striking against an adobe wall.
This species of penstemmon (as are most wild species) is native to the western mountains of North America. It likes cool, somewhat dry climates and will probably rot in Midwestern or eastern gardens because of humidity and general dampness.
There are, however, a number of eastern North American natives that are acclimated to gardens which receive a good deal of precipitation (over 20 inches a year).
I love penstemmons for a number of reasons. They are absolutely gorgeous when in full bloom, and they are long bloomers. They are also great for cut flowers, accenting any arrangement with their elegance.
Hummingbirds love them, and will spend the whole day in your garden if you have a number of penstemmons planted. In winter, small birds will hang onto their sturdy stalks and pick seeds from the small pods. Or, they will gather around the stalks and pick the seeds from the ground. This is particularly attractive when it snows. Wind and large snowflakes striking the tiny pods send cascades of the tiny seeds into the snow, where chickadees and other small birds will congregate The seeds resemble poppy seeds.
Penstemmons are perennials, and generally will die back to the ground during winter, greeting you with their unique foliage in mid-spring. I do have some penstemmon (penstemmon digitalis), which appeared in my garden one day, that refuses to die back, and is one of the first flowers to greet me in the spring (after the daffodils, hyacinths and tulips). These penstemmons send up dozens of tall bracts sometimes three feet or more, and are pale pink.
It will reseed readily, although the seeds do need stratification. If left alone, they will do this on their own, or the small birds which dine on them will often do it for you.
I do not give my penstemmons any special treatment. They prefer dryer conditions, and don't need nutrients added to the soil for them to thrive.
They grow well in containers, as long as they're not over-watered.
Here are some varieties you might consider:
Penstemmon australis - grows to three feet, with six-inch-long leaves. Pale pink flowers with deep red stripes. Zones 5 to 9.
Penstemmon pinifolius - one to two feet tall. Shrub-like. Tubular, scarlet flowers. Zones 6-8.
P. digitalis - (foxglove penstemmon) Two to five feet tall and the leaves can grow to 8 inches. The flowers are about 1 inch long and are white. There are cultivars of this variety. Zones 4-8
P. barbatus - grows from 1 ½ to three feet tall, leaves are lance-shaped and gray-green in color. The flower spikes are pink to carmine. Cultivars include "Bashful" with salmon-colored flowers, "Elfin Pink" with bright pink flowers and "Beauty" with pink flowers. Zones 3-8
In a desert garden, penstemmons should be planted in the transition or arid zones. They prefer full sun, but will tolerate light shade. The plants form dense clumps and should be divided every four to eight years.
Penstemmons look great any where, and you can experiment with them to obtain the most striking combinations. I have some growing amidst yarrow, purple coneflowers, roses, and even alone, where they make amazing color statements.
Next: Roses in a desert garden.
