Fraser, L., R. Turkington, and C.P. Chanway, 1993. The biology of Canadian weeds. 102. Gaultheria shallon Pursh.  Can. J. Plant Sci. 73:1233-1247.

G. shallon is a densely growing perennial evergreen shrub occurring only from the panhandle of Alaska along the entire coast of British Columbia to southern California; it is of native origin. G. shallon grows on a wide range of soil types and textures, and is abundant in open habitats near the coast particularly on rocky knolls and along bluffs. It is a persistent, pervasive woody perennial and is a serious competitor with coniferous species [Pinopsida]. The plant produces numerous seeds but the most significant and effective form of colonization is through vegetative spread. Several herbicides are recommended for control of the weed but it is both resistant and resilient to many herbicides. A summary of the known biological data for this species is presented.