The valleys are covered with typical desert shrubs; greasewood (sarcobatus vermiculatus), creosote bushes (larrea tridentata), and sage-brush (artemisia tridentata); the first-named plant is abundant, chiefly in the N.
Among other plants common to the state are the elder, wild hop, dwarf sunflower, and several species of greasewood and cacti.
There are firs and spruces on the mountains, characteristic of the Boreal zone; pines characteristic of the Transition zone; pinon juniper, greasewood and the universally conspicuous sage-brush, characteristic of the Upper Sonoran zone.
In the valleys the only trees native to the soil are the willow and cottonwood, found along the water courses, and beyond the range of irrigation vegetation is limited to scanty grass, with sage-brush and greasewood in the N.
New Mexico has such a great range of elevations that all four of the zones of vegetation into which the South-West has been divided according to altitude are found within its limits; namely, the zone of cactus, yucca and agave (3000-3500 ft.), where grass is scanty; the zone of greasewood and sage-brush (3500-4900 ft.), where there is little grass, and the cactus species are less numerous; the zone of the cedar (4900-6800 ft.); and the zone of the pine and fir (6800 - 10,800 ft.), in which grass is more abundant.