[11][1] He described it from a specimen collected by Dr. John Milton Bigelow made in October 1853 in the Sandia Mountains of New Mexico.

In the same issue he inadvertently described another specimen of P. whippleanus collected in Colorado by Charles Christopher Parry as Penstemon glaucus var.

[13][14] In 1899 another collection was incorrectly described as a new species, Penstemon arizonicus, by Amos Arthur Heller in the Bulletin of the Torrey Botanical Club.

[15] American botanist Thomas J. Howell reclassified Asa Gray's variety of P. glaucus as Penstemon stenosepalus in his book A flora of northwest America in 1901.

[17][18] In 1920 Francis W. Pennell reevaluated Asa Gray's identification of the specimen collected near the headwaters of Clear Creek as P. glaucus var.

[22] Penstemon whippleanus is widely distributed in the central Rocky Mountains of North America.

[24][25] In garden conditions they grow in neutral to acid soils and spread rapidly; they are also tolerant of propagation by division.

[23] In the garden they are, like most members of the genus, drought tolerant but intolerant of poorly draining soils or waterlogged conditions.

They are resistant to browsing by deer,[25] but young plants in garden settings are often damaged by eleworms, slugs, or snails.

[24] They are also vulnerable in garden settings to powdery mildew, rust, leaf spots, and Southern blight.