[1] It is a herbaceous perennial plant that typically grows to a height of 20 to 50 cm (8 to 20 in) and has narrow, lance-shaped leaves that are grayish-green in color.

It is sometimes used in xeriscaping, rock gardens, and wildflower meadows, and is well-suited to dry, sunny locations with well-draining soil.

It usually dies back fully each year, but may retain some leaves over the winter or have a slightly woody above ground stem, called a caudex, that it will re-sprout from in the spring.

[5] The leaves are entirely smooth, free of hairs, and somewhat gray-green in color from the natural waxes that protect the plant from drying out (glaucous).

The smooth flowering stems are between 15 and 50 cm (6 and 20 in) in height and usually stand straight upright, but occasionally with a curve at the base.

It has an abruptly recurved tip, divided into two branches, and the dense hairs covering its end are golden yellow and 2 mm long.

[4] It was first described in Prodromus Systematis Naturalis Regni Vegetabilis volume 10 in 1846 by George Bentham as Pentstemon secundiflorus using the mistaken Linnaean correction of John Mitchell's Penstemon and botanical Latin secund 'one-sided' and florus 'flower'.

[11][1] In 1906 Per Axel Rydberg described a new species, Penstemon unilateralis, in the Bulletin of the Torrey Botanical Club from a collection by Asa Gray in 1878.

[12][13] Pennell also described a dwarf variant of the species he found in South Park, Colorado as Penstemon secundiflorus var lavendulus.

[12] However, it is no longer generally accepted as a subspecies despite the distinctive narrower leaves and noticeable red-violet corollas.

[14] However, the general appearance is almost identical to Penstemon secundiflorus and can only be visually distinguished by the lack of hairs on the staminode and narrower more green colored leaves.

[22][21] Penstemon secundiflorus is commonly found growing in rocky, gravelly, and sandy loam soils.

[4] P. secundiflorus tend to be scattered through its habitat, with two or three plants in each location, rather than forming continuous stands or dense colonies.

[24][14] The locations of populations in Mexico are not precisely recorded, but POWO reports it grows in the states of Sonora and Chihuahua.

[25] As would be expected from the relatively large and brightly colored flowers, Penstemon secundiflorus has many nectar feeding visitors.

[27] In one field observation bees of the genus Lasioglossum were the most frequent visitors to the flower, but the exact species was undetermined in that study.