Why Does The West Have Lawns?

Irrigated bluegrass blankets many western cities. Why is this tradition so rooted? "..Instead of adapting themselves to the landscape, the Colorado immigrants of 1860-1900 worked very diligently to adapt the landscape to themselves."They didn't look at such plants as grew around here and find uses for yucca and prickly pear. Instead, they cleared fields and dug ditches and sowed the plants they were familiar with...The New Mexico colonists who got here a little earlier had their own visions of how towns should look. The plaza with the church, not the railroad depot, was the focal point. Rather than build frame houses that needed extensive heating systems, they used thick adobe walls fabricated from local mud. Rather than install yards with lawns for greenery, they built sheltered courtyards so that the harsh sun and wind wouldn't desiccate their plants."