The Plant Guide is an online field guide for plants of the northern Rockies. Much of the information is focused on describing the common plant species found near Missoula and Ravalli counties in western Montana.

Plants in western Montana

Plants are key to habitats of wildlife, and as primary producers largely determine the biological productivity of ecosystems. They also play major roles in nutrient recycling and fire. Plants are quite diverse.

While much is known about a few species of economic importance, there is much to be learned about the basic ecology of most species. Upwards of 20,000 species of vascular plants (not including mosses, liverworts, lichens, fungi) occur north of Mexico in North America. Approximately 1,500 species of plants are known to occur in Missoula and Ravalli counties alone, which includes most of the species known to occur in Montana.

While in disturbed grasslands in low elevation valleys it is easy to get the impression that most of our plants are invasive exotic weeds, even in these habitats there is a rich variety of native plant species. Only about 200 species are exotic in the state, although every year more get established here. On Mount Sentinel alone 200 species have been documented to occur on its dry western slopes.

We have a rich variety of plants here primarily because western Montana is a biological crossroads between the Great Basin in Idaho and Utah, the coastal Pacific Northwest, the Great Plains, and the boreal forests of Canada.

Western Montana also has a complex geological history. Many ancient remnants of continental crusts, recent volcanic deposits, rich alluvial deposits, and mineral-rich metamorphosed rocks are distributed over a highly varied topography and landscape.

Few plant species are unique to Montana, but many are threatened and of conservation interest.