The War on Weeds

Dr. Patrick W. Colgan is Director of Research and Natural Lands at the
Royal Botanical Gardens.

Evans, experienced with the western weed industry, has turned to
recounting the importance of weeds in the history of the Canadian
prairies, highlighting the shortcomings of legislation and bureaucratic
systems while demonstrating the natural and economic significance of
weeds. He discusses the subjective nature of the concept “weed,” and
the germane issues of plant introductions and competition. He then
reviews the battle against weeds in British agricultural history from
the 16th through 19th centuries in terms of key reformers and practices
such as tillage and crop rotation.

Agriculture in Upper Canada during the first two-thirds of the 19th
century was characterized by intensive use of land, expensive labor, and
conflict with weeds. During the latter third of the century, these
militant attitudes and practices moved westward to the prairies. Evans
relates how the Ontario Agricultural College and chain of Dominion
Experimental Farms were established and staffed during this period, with
accompanying publications and legislation concerning weeds. He also
describes the parallels with western farmers in the United States, the
role of technology in the form of tractors, and the economic hardships
created by weeds and drought.

With the advent of 2,4-D in 1945, the story takes on new dimensions.
Although Evans gives a history of chemical approaches using chlorates
and hormonal compounds, it is regrettable that he does not outline the
mechanism of 2,4-D. He does describe the development of resistant
strains of weeds, the problems with wild oats, and conservation issues
made prominent by Rachel Carson.

Evans’s narrative smoothly flows into the more general issues of
adversarial versus co-existential approaches to the land, the importance
of balanced husbandry, and human–nature interactions. The tale is
satisfyingly placed in the larger context of western agriculture and
historiography. The book is illustrated with monochrome and color
drawings of weeds, and thoroughly researched and indexed. A treat for
everyone interested in agriculture, weeds, and western social history.