Perennial of the Plantaginaceae family, Penstemon grandiflorus is native to the Great Plains of central North America, from South Dakota to Texas, where it grows in dry prairies and open sandy areas, at low to medium altitude.
The species is one of the most imposing of the genus. It raises rigid and fleshy stems that can reach 60 to 90 cm, adorned with oval to elliptical leaves, thick, very glaucous, of a remarkable ash blue-green, amplexicaul, which partially envelop the stem. This sculptural foliage is one of the major attractions of the plant, regardless of the flowering.
The cultivar 'Prairie Snow' was selected for its pure white flowers, where the type species bears pink-lilac to lavender flowers. The flowers are tubular-bilabiate, very large, slightly creamy in bud state, arranged in well-spaced whorls along the upright stem. This selection is one of the few to offer white in a genus dominated by pinks and blue-violets. Seedlings from this cultivar do not necessarily reproduce the white color faithfully.
In its natural habitat, the species blooms from May to July. In cultivation, it generally occurs in June.
It requires a very well-drained soil, dry to moderately fresh, poor to moderately fertile, in full sun. Stagnant winter humidity is unfavorable to it. Generally a short-lived plant, it self-seeds spontaneously in the garden.