Writing as I did yesterday about Hoover dam and the hydraulic theory of history, I came to think also of the American institution of lawns. In other countries, homeowners have plots and they do various things to garden and decorate their plots. But in America, everyone seems agreed on the proper way to decorate your plot: blade after blade of grass regularly mowed to keep all the blades to a uniform height, the congeries of blades as dense as possible to convey a sense of lushness, as much like your neighbor's as possible -- except a darker green -- to lull him with your conformity to type while also driving him mad with envy. Michael Pollan wrote back in 1989 that the standard issue lawn was like the interstate highway system, or fast-food franchises. Together, these innovations make "the suburbs of Cleveland and Tucson, the streets of Eugene and Tampa, look more alike than not." The love of lawns goes back a long time. Gatsby, in Fitzgerald's novel, sends a ...