There is still some disagreement about the name of and characteristics of this plant:  

   1)  Both Weber and Intermountain Flora state that our widely distributed and highly variable common Erysimum is  E. capitatum and that E. asperum is a plant of the plains, primarily differing from S. capitatum by having seed pods that are quite hairy and extending almost at right angles from the stem. E. capitatum seed pods are smooth and nearly vertical (almost parallel to the stem). Weber states that on the West Slope E. asperum exists only in the far northern counties.

   2)  Stanley Welsh, who almost always retains the plant names used by Intermountain Flora, takes a very different position and states that all of the Utah plants (and I infer, West Slope Colorado plants also) are E. asperum, i.e., E. capitatum is really E. asperum.

   3)  Based on the collections of Heil and O'Kane for their Flora of the Four Corners book, The Synthesis of the North American Flora recognizes both species in the Four Corners area.  (See range maps below.)

    "Capitatum" (Latin for "head", as in "decapitate’) refers to the rounded, head-shaped flower cluster.  Asperum" means "rough".

Click for the wild colors of Erysimum capitatum. 

Erysimum capitatum (Wallflower)
Brassicaceae (Mustard Family)

Semi-desert to alpine. Woodlands, meadows. Spring, summer.
Canyons of the Ancients National Monument, April 19, 2016 and April 18, 2014.

At the lower elevations of the Four Corners region, Erysimum capitatum is often found at the base of Juniperus osteosperma, Utah Juniper.

Erysimum capitatum (Western Wallflower)
Brassicaceae (Mustard Family)

Semi-desert to alpine. Woodlands, meadows. Spring, summer.
Canyons of the Ancients National Monument, February 4, 2015 and March 17, 2005.

Erysimum capitatum is a handsome plant often brightening the dry-brown duff under Junipers and Pinyons in the early spring. In the first photograph at left, the over-wintering basal rosettes are evident. In the second photograph a quite young, short, and vibrant green plant flowers in mid-March.

Erysimum capitatum is a wide-spread, common, and highly variable species.  Stanley Welsh indicates that this plant "demonstrates greater ecological latitude than any other Utah plant; it occurs from the lowest to the highest elevations in the state". Erysimum capitatum is, in William Weber's words, "extremely variable".

Linnaeus named the Erysimum genus from the Greek word "eryomai", "to help" because of the medicinal properties of the plants. Latin gives us the "capitatum" for "head", referring to the ball-like, head-like flower cluster (see below).

Erysimum capitatum (Western Wallflower)
Brassicaceae (Mustard Family)

Semi-desert to alpine. Woodlands, meadows. Spring, summer.
Canyons of the Ancients National Monument, April 1, 2005.

Several weeks later, plants in the same area as those above left are over a foot tall and the spreading and then ascending seed pods (siliques) have begun maturing (just to the right of the curved leaf below center right).

Erysimum capitatum (Western Wallflower)
Brassicaceae (Mustard Family)

Semi-desert to alpine. Woodlands, meadows. Spring, summer.
Sharkstooth Trail, June 28, 2007.

At lower elevations Wallflower blooms in the very early spring; later in the summer (as shown at left) it can be found above tree line in open meadows.  From habitat to habitat it ranges from just a few inches tall to well over two feet. 

Although flowers are most often vibrant lemon yellow, they can be greenish-yellow (as shown below), cream, or even lavender. 

Erysimum capitatum grows solitary, in small groups, or scattered over a large area.

Erysimum capitatum (Western Wallflower)
Brassicaceae (Mustard Family)

Semi-desert to alpine. Woodlands, meadows. Spring, summer.
Sharkstooth Trail, June 28, 2007.

Erysimum capitatum (Western Wallflower)
Brassicaceae (Mustard Family)

Semi-desert to alpine. Woodlands, meadows. Spring, summer.
Big Bear Pass, July 20, 2008 and
Canyons of the Ancients National Monument, April 23, 2016.

The narrow and nearly vertical seed pods of the dwarf alpine Erysimum capitatum in the top photograph at left are two inches long.  Those in the second photograph are three inches long. At all altitudes, pods range from one to four inches long.

Click to see the wide color variation of Erysimum capitatum.

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 Erysimum asperum

Range map for Erysimum capitatum