"From the colonial period through the middle of the nineteenth century, hemp was widely grown in the United States for use in fabric, twine, and paper.19 Production dropped by the 1890’s as technological advances made cotton a more competitive textile crop, and coarse fiber crops were increasingly imported.20 Nonetheless, American farmers continued to grow hemp into the middle of the twentieth century, finding it a useful rotation crop because it acted as a natural herbicide21—a dense, rapidly growing crop, it choked out weeds prior to the next planting of corn and other crops.22 At the urging of the government, production to supply fiber for military purposes was expanded enormously during World War I and again during World War II, particularly after the Japanese cut off exports from the Philippines."
Kolosov, Christine A. Evaluating the Public Interest: Regulation of Industrial Hemp under the Controlled Substances Act. UCLA Law Review. Los Angeles, CA: UCLA School of Law, 2009.