Hagerman Fossil Beds National Monument - Trees and Shrubs

Throughout the Monument native vegetation, including big sagebrush and rabbitbrush, survive among the lava rock boulders. Flora on the upland plateau was once a vast complex of Wyoming big sagebrush ( Artemisia tridentata ) association but some of the Monument"s west boundary areas were cleared and now support common rabbitbrush ( Chrysothamnus nauseosus ), and introduced grasses and weeds.

Vegetation on the bluffs is sparse in many areas due to the steepness of the slopes and low precipitation (less than 10 inches a year). Greasewood ( Sarcobatus vermiculatus ) and rabbitbrush are the dominant shrubs where the soil is more alkaline. Scattered occurrences of four-wing saltbush ( Atriplex canescens ) occur where soils contain more calcite. Russian thistle ( Salsola kali ), the ubiquitous tumbleweed, predominates on disturbed sites.