Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)


Geography and Anthropology

First Advisor

Kent Mathewson


By all accounts, the peoples of the Northwest Coast of North America did not cultivate plants at the time of European contact. This dissertation provides an interdisciplinary assessment of evidence to the contrary, and presents a critique of the literature from which this orthodoxy has been derived. As a primary line of evidence, this thesis describes estuarine gardens found on this coast during the contact period. Northwest Coast peoples created gardens of Pacific silverweed (Potentilla anserina ssp. pacifica), springbank clover (Trifolium wormskjoldii) and other plants with edible, starchy roots within estuarine plots. Ethnographic sources suggest that these gardens were maintained through transplanting, weeding, selective harvesting, and a host of other management methods. Such sites were termed "gardens" by Franz Boas and others, but were dismissed as "non-agricultural" in part due to the restrictive definition of agriculture which prevailed in Boas' time. Indigenous motives for plant resource intensification paralleled the post-Pleistocene intensification of other resources, as sedentary villages developed around productive estuaries where salmon and other resources were concentrated. Ethnographic evidence suggests that Northwest Coast peoples had strong economic, dietary, and ceremonial motives to enhance rhizome output, which evolved alongside these long-term trends in dietary and settlement patterns. Gardens represented an elegant response to these motives. With mounded soils, often encircled by rock enclosures, these gardens dramatically expanded the narrow zone where these edible plants grow. Anomalously porous and nutrient-rich garden soils further enhanced rhizome output. Linguistic evidence suggests that indigenous peoples recognized gardens as a product of human agency, and as "places of manufactured soil." Gardens recorded during the colonial period can be found archaeologically, and probable garden sites with similar structural characteristics can be found dotting this coastline. Archaeological evidence conducted for this dissertation demonstrates that these gardens were being intensively managed prior to European contact. Similar wetland gardening methods from the American tropics are explored, as is the demise of Northwest Coast wetland gardening in the colonial period. Cumulatively, this dissertation concludes that Northwest Coast estuarine gardening constitutes a tradition of "plant cultivation," by current definitions of that term.