It’s that time again—when the spring bulbs have faded, the monsoons haven’t arrived, and the landscape seems parched. But look closely: the penstemons are having their moment in the sun. These hardy native perennials are lighting up roadsides, rocky slopes, and well-tended xeric gardens with vibrant spikes of color. If you’re looking for plants that thrive in this hot, dry gap, Penstemon strictus and Penstemon cardinalis are true dynamos.
Penstemon strictus, or Rocky Mountain Penstemon, puts on a show with deep blue to purple blooms that stand tall and proud. It’s native to higher elevation regions across the Intermountain West and does well in full sun to partial shade. It prefers well-draining soils (think gravelly or sandy) and doesn’t need much water once established.
Penstemon cardinalis, or Cardinal Penstemon, is a hummingbird magnet with brilliant red tubular flowers. It’s one of the latest blooming penstemons and actually lives longer in nutrient-poor well draining soil.
Unassuming Penstemon cardinalis in the greenhouse.
Penstemon strictus patch at the Ramada.
Up close view of Penstemon strictus.
Both species are low-maintenance and drought-tolerant once they’ve settled in. Water young plants regularly their first season, but don’t spoil them—these natives prefer tough love. Avoid rich soils or overwatering, which can cause rot. Deadhead if you want to prolong blooming or let them go to seed to naturalize in your garden. Either way, they’re happiest in wild-ish, well-draining spaces where they can bask in the sun and bloom like they mean it.
So if your garden’s feeling a little crispy right now, penstemons might be the cure. Plant them this fall or early next spring, and next year you’ll be rewarded with color right when most other plants are waving the white flag. It’s penstemon season—lean in!
Sarah Armanovs is the Gardens Manager at The Arboretum at Flagstaff.
