The species was named  by famed collector and Harvard Professor, Thomas Nuttall in Torrey and Gray's 1838 Flora of North America.  Nuttall was also the first to collect this plant, probably in 1835, on his trip west with the Wyeth Expedition of 1834-1837.

Semi-desert, foothills, montane. Disturbed areas, openings. Spring, summer.
Butler Wash near the San Juan River, Utah, April 8, 2005.  Canyons of the Ancients National Monument, May 11, 2011.

Western Peppergrass is abundant in Pinyon/Juniper forests and is also common in the mountains.  One very common spring blooming variety (pictured at left and directly below) has many stems, making it almost appear to be a small shrub.  It grows two feet tall.

Weber lists seven varieties of Lepidium montanum on the West Slope of the Rockies in Colorado.  Welsh lists eight varieties in Utah and has this to say about Lepidium montanum: "There is an amazing amount of variation within L. montanum....  There is justification for recognizing all of these [as species]...." 

Semi-desert, foothills, montane. Disturbed areas, openings. Spring, summer.
Butler Wash near the San Juan River, Utah, April 8, 2005.  Canyonlands National Park, Utah, April 12, 2005. 

Lower leaves are lobed or broadly pinnatified (in this case, with few lobes, similar to a fleur-de-lis); upper leaves are usually linear.

An abundance of tiny, fragrant, white flowers is the main attraction of this very showy and common plant. 

Semi-desert, foothills, montane. Disturbed areas, openings. Spring, summer.
Canyons of the Ancients National Monument, April 1, 2005.

As noted above, Lepidium montanum is a highly variable species.  The very early spring blooming variety at left looks quite different from the varieties above and below.  This variety has few stems, an open growth pattern, and grows to only a foot or so tall.  Its basal leaves have many lobes. 

Semi-desert, foothills, montane. Disturbed areas, openings. Spring, summer.
Canyons of the Ancients National Monument, August 22, 2005.

This tall, late summer blooming variety of Lepidium montanum is very common and long-lasting in Pinyon/Juniper forest openings and along roads.  Flowers and seeds are very similar to the other L. montanums shown on this page.  Basal leaves are, however, usually withered at blooming time.  Stems may be single or multiple from the base and may branch at about a forty-five degree angle from anywhere on the stem but there are usually few branchings.  As a result the plant has a very open and airy appearance and it is top-heavy with flowers and seeds.

Range map © John Kartesz,
Floristic Synthesis of North America

State Color Key

Species present in state and native
Species present in state and exotic
Species not present in state

County Color Key

Species present and not rare
Species present and rare
Species extirpated (historic)
Species extinct
Species noxious
Species exotic and present
Native species, but adventive in state
Eradicated
Questionable presence

Range map for Lepidium montanum