Earth Notes: Sunset Crater Penstemon

Flagstaff, AZ –

Living conditions are harsh among the cinders in the volcanic terrain that spreads northeast of Flagstaff. But for one plant they're an irreplaceable home. The Sunset Crater penstemon, or Penstemon clutei (pron. cloo-tee-eye), lives nowhere else.

That selectivity has made the plant rare only 36 wild clumps are known to exist. The Center for Plant Conservation has made it an officially "sponsored species" with its own endowment.

The plant's official caretaker, Flagstaff Arboretum, uses this money to undertake annual monitoring and maintenance of a seed bank for research. The plant's status is currently considered stable. But its vulnerability to grazing, trampling by hikers and off-road vehicles, as well as climate change, means that ongoing protection is vital.

Like most penstemons, the plants have waxy, serrated leaves and several stems up to 32 inches tall. Between late April and early August they form beautiful bright pink tubular flowers with a swollen belly-like protuberance at the bottom.

Indeed the beauty of these flowers has made the plant popular with gardeners, and cultivation is helping its population to grow. You could grow a specimen in your yard if you have the right conditions. The Sunset Crater penstemon doesn't like competition from other plants and needs hot dry cindery soil in a sheltered location to thrive.

To learn about this and related native plants, visit the Flagstaff Arboretum's annual Plant Sale and Penstemon Festival this year, it will be held on July 10.

-Diane Hope