October is the best time of the year to plant Penstemon wildflower seeds here in southern Arizona. These native, spring-blooming wildflowers are easy to grow and are moderately drought tolerant once established. Penstemons have large, showy flower stalks that attract hummingbirds and large butterflies, especially Pipevine Swallowtails (Battus philenor) here in Tucson.
Penstemons (Penstemon spp.) are perennials, so these plants will live and bloom each spring for several years. Penstemons will easily reseed themselves, and their abundantly produced seed is also very easy to collect and use for later sowing. When using gathered seed, be sure to remove the seeds from the seed capsules before planting.
Here's how to plant Penstemon wildflower seeds:
- Plant in the fall during warm weather.
- Before planting, choose a growing site with full sun.
- Remove any weeds and unwanted rocks.
- Loosen the upper soil surface with a stiff rake.
- Mix the Penstemon seeds with four parts soil or sand.
- Evenly spread the seed/soil/sand mixture on the sowing site.
- Lightly rake the soil in one direction only to lightly cover the seeds.
- Water daily (depending on temperature and rain) until all the plants have sprouted.
- Reduce watering to every few days to weekly as the plants become established.
- Occasional watering will keep the established plants growing, but too frequent watering causes powdery mildew.
Native Penstemons that will do well here in southern Arizona:
I have discovered half a dozen different species of Penstemon growing wild here in the Tucson area. These wildflowers are most common in the upper foothills and in upland areas around 4000 feet (1219 m) in elevation where they can get a little extra water.
Pink-flowered Desert Penstemons or Arizona Penstemons (Penstemon pseudospectabilis) can be recognized by their toothed, boat-like upper leaves which completely surround the stems.
Red-flowered Eaton's Penstemons or Eaton's Firecrackers (Penstemon eatonii) can be found growing both in Tucson and in upland areas around Tucson, such as along the Catalina Highway in the Santa Catalina Mountains.
Unlike these other Penstemons, the pale pink-flowered Palmer's Penstemons (Penstemon palmeri) have a delightful fragrance, similar to that of roses. Like Desert Penstemons, they also have boat-like upper leaves, but the leaves of Palmer's Penstemons are an unusual powdery blue-green color.
Although they can be found growing in upland areas around Tucson, red-flowered Beardlip Penstemons (Penstemon barbatus) are much more common in the mountains, and I frequently see them amidst the oaks and pines in the Santa Catalina Mountains.