- COLORADO STATE UNIVERSITY COOPERATIVE EXTENSION TRI RIVER AREA Trees and Shrubs of Western Colorado Mesa, Delta, Montrose and Ouray Counties Problems and Care the Gardening and Horticulture Web Pages General Information The Globe Willow - Salix matsudana `Navajo' This tree is a very common sight in the warmer parts of the Tri River Area. This discussion provides the history, problems and ...www.colostate.edu/Depts/CoopExt/TRA/PLANTS/tree.html