Sometime in the 1870s, Pringle began to collect plants throughout Vermont, from deep in mossy woods, by lakesides, or high on mountain summits. On December 13, 1874, he was appointed to the Vermont Board of Agriculture. During three successive years he took boat trips up the lower St. Lawrence to the Saguenay Rivers in Canada, and the St. Francis and St. John Rivers of northern Maine. In 1878, he displayed many of the Vermont specimens which he had been collecting at the Paris World's Fair.