Yards have been used for centuries to enhance the beauty of large aristocratic mansions. By the time of the Revolutionary War, the open yard had become a distinctive feature of American culture. Open yards allowed colonial neighbors to keep a watch on each other's homes. In England, the open yard concept was imported from China during the Victorian era. The most important tool of lawn maintenance is the lawn mower. Although similar in function to agricultural mowing machines, the lawn mower is actually an adaptation of a nineteenth-century rotary shearer that was used to remove the nap, or excess fiber, from carpets. Englishman Thomas Plucknett is credited with inventing a mowing machine in 1805. It consisted of a revolving blade mounted between a pair of carriage wheels and was capable of indiscriminately cutting all types of grasses, including grain. The first mower specifically designed for keeping lawns...