pesticides, fertilizers, and herbicides. The environmental impacts of this widespread chemical use were noticed as early as the 1960s, but suburban lawns as a source of pollution were largely ignored. Organic lawns Due to the harmful effects of excessive pesticide use, fertilizer use, climate change and pollution, a movement developed in the late 20th century to require organic lawn management. By the first decade of the 21st century, American homeowners were using ten times more pesticides per acre than farmers, poisoning an estimated 60 to 70 million birds yearly. Lawn mowers are a significant contributor to pollution released into Earth's atmosphere, with a riding lawn mower producing the same amount of pollution in one hour of use as 34 cars. In recent years, some municipalities have banned synthetic pesticides and fertilizers and required organic land care techniques be used. There are many locations with organic lawns that require organic landscaping. In the 2020s, lawn alternatives and more eco-friendly lawn management began increasing greatly in popularity, with the help of social media. United States Prior to European colonization, the grasses on the East Coast of North America were mostly broom straw, wild rye, and marsh grass. As Europeans moved into the region, it was noted by colonists in New England, more than others, that the grasses of the New World were inferior to those of England and that their livestock seemed to receive less nutrition from it. In fact, once livestock brought overseas from Europe spread throughout the colonies, much of the native grasses of New England disappeared, and an inventory list from the 17th century noted supplies of clover and grass seed from England. New colonists were even urged by their country and companies to bring grass seed with them to North America. By the late 17th century, a new market in imported grass seed had begun in New England. Much of the new grasses brought by Europeans spread quickly and effectively, often ahead of the colonists. One such species, Bermuda grass (Cynodon dactylon), became the most important pasture grass for the southern colonies. Kentucky bluegrass (Poa pratensis) is a grass native to Europe or the Middle East. It was likely carried to Midwestern United States in the early 1600s by French missionaries and spread via the waterways to the region around Kentucky. However, it may also have spread across the Appalachian Mountains after an introduction on the east coast.