Slate has up the history of the broom:
Modern broom-making truly began, however, with the rise in cultivation of a previously underappreciated crop that would soon be called “broomcorn.” A species of tasseled grass (sorghum vulgare) that somewhat resembles the sweet corn plant, broomcorn’s seeds and fibers had previously been used for animal feed and not much else. Then, according to historian Gregory H. Nobles, in 1797, a farmer from Hadley, Mass., named Levi Dickinson had the idea to use the grass to make a broom for his wife, as well as a few extra to peddle to neighbors. His broom—a round bundle of broomcorn lashed to a stick with some weaving around the top—proved to be more durable and effective than previous models, and it was soon in demand around the region. By 1800, Dickinson and his sons were making several hundred brooms a year to sell throughout the northeastern United States.
Other farmers quickly planted acres of broomcorn and joined the trade, as broom cultivation and construction was a fairly simple side-job that could fit easily into the pre-established rhythms of agricultural life. By the first few decades of the 19th century, a number of versions of the “broom machine”—a set of vices, clamps and a foot treadle (essentially a tension apparatus that uses the broom-maker’s feet to keep a roll of twine taut as he winds it around the broom corn)—had been developed that made broom manufacturing even quicker.