In the Midwest, my first exposure to the penstemons was ‘Husker’s Red’, a cultivar of Penstemon digitalis with white flowers and red spring foliage. Spending time later in Arizona, I was happy to see penstemons well-represented in the Western states. In fact, most areas of the continental United States sport penstemons: wild, cultivated or both. This genus in the figwort family or Scrophulariaceae offers many garden-worthy species. The Western states are especially rich with many beautiful penstemons. In the desert Southwest, Parry’s penstemon or Penstemon parryii as it is known to science, is a garden favorite.
Parry’s penstemon delivers bright pink flowers on tall scapes throughout the late winter and into spring. In Tucson, Zone 9b, this means February through April. Individual plants are typically two feet wide and as tall or taller. Leaves are roughly six inches long and arise from solitary clumps. Foliage is mostly green, with blue and red tones interspersed.
In landscapes, P. parryi is often included in spring wildflower plantings, mesic situations and even cactus gardens. It is quite adaptable and looks great almost anywhere. Masses of plants are most dramatic. Combinations involving the blue-greens of agaves and Dasylirion are especially striking. These succulents also help offset this penstemon’s dull dormant appearance. In the flower garden, P. parryi combines best with other pink, blue or white blooming plants. The blue flowers of another Southwestern native, bluebells or Phacelia campanularia, make an especially nice complement.
Growth commences in late fall, and Penstemon parryi grows best with regular winter rains. In Tucson, rainfall alone is satisfactory. Nevertheless, supplemental water helps offset dry conditions. Parry’s penstemon withstands temperatures of 20 degrees F and lower while actively growing. After seed set, plants rest during the long and hot summer. During this period, plants get by on minimal moisture despite weeks of high temperatures topping 100 degrees F. Individual clumps can live for a number of years, but younger plants tend to be stronger and bloom better. Plants will grow in sun or shade and tolerate the wide range of soil conditions found in the west.
Division is certainly possible, but seed is easy and the primary means of propagation. Plants are self-fertile and produce copious amounts of seed. With good winter rains, seedlings will germinate, grow and bloom within a few months. This leads one to wonder if this species might have potential outside the Southwest as an annual. I have seen aphids on the bloom stalks, but by no means are they a serious pest. For the most part, Parry’s penstemon is remarkably pest-free.
Parry’s penstemon is a star in the Southwestern landscape. The profusion of pink flowers is a welcome spot of color. The plant seems at home in nearly every garden and is easy to grow. It is among the many penstemons that offer beauty and landscape potential in our modern green spaces.
Freelance garden writer