The Rock Penstemon, Penstemon baccharifolius Diablo™ ,is one of many penstemons to choose from for Tucson area landscaping. As a native to south Texas, it certainly does not mind our desert heat!
The Rock Penstemon is more on the shrub-side, even though it is considered a perennial. The rosy-red flowers appear in the spring and summer, which is a slightly different schedule than the species that only bloom in the spring. The plant matures quickly at about 2 feet tall and wide.
As with all Penstemons, the Rock Penstemon is frequently by hummingbirds, and is a great choice to tuck in between other plants in your yard to hide its dormant period. All penstemons need good drainage, and hate over-watering, so be careful to make sure you provide both well-drained soils and do not water too much. Planting under a native mesquite tree is an ideal location, since it prefers a break from our hot summer sun.
Reference: Mountain States Wholesale Nursery and Gregg Starr Nursery Plant Info Sheet, 1999.