For the purpose of this blog, I'll focus on Rocky Mountain elk (Cervus elaphus nelsoni) although there is overlap with other subspecies.
In spring and summer, elk are primarily grazers, eating grasses.
As spring turns to summer and the grasses die out, elk start to depend more on and forbs (small plants that grow in the forest), which stay green longer than some grasses. As winter approaches, elk increasingly act as browsers, feeding on the sprouts and branches of shrubs and trees, including pine trees.
I'll start with spring time browse and work my way to fall. I can tell you from personal experience, elk eat a variety of plants, but for the sake of brevity, I'm focusing on those species that are 'preferred' food of elk. These may change due to weather conditions, region, and pressure, but I hope this is a good starting point. I've included a link to pictures of each of the species.
Grasses and Sedges
Blue Bunch Wheatgrass, Pseudoroegneria spicata
Elk Sedge, Carex geyeri
Mountain Brome, Bromus marginatus
Orchard Grass, Dactylis glomerata
Idaho Fescue, Festuca idahoensis
Forbs
Sweet clover, Melilotus spp.
Clover, Trifolium spp.
Miners Lettuce, Claytonia spp.
Dandelion, Taraxacum spp.
Fireweed, Epilobium angustifolium
Yellow salsify, Tragopogon spp.
Shrubs and Groundcover
Red-twig dogwood, Cornus sericea
Snowberry, Symphoricarpos albus
Serviceberry, Amelanchier alnifolia
Wild rose, Rosa spp.
Currant, Ribes spp.
Deer brush, Ceanothus integerrimus
Elderberry, Sambucus spp
Huckleberry, Vaccinium spp.
Oceanspray, Holodiscus spp.
Sumac, Rhus spp.
Bitterbrush, Purshia tridentata
Trees
Aspen, Populus tremuloides
Chokecherry, Prunus virginiana
Cottonwood, Populus trichocarpa
Rocky mountain maple, Acer glabrum
Mountain Ash, Sorbus americana
Willow, Salix spp.
Western Red Cedar, Thulja plicata
