The lawn in my front yard has been converted to desert landscape except for the hedge of roses that surrounds the immediate front yard. About 47 Sunsprite Roses, and a few misc. in the background, Lyda Rose, Knock Out, and a few others whose name eludes me right now. Most of the back yard is desert landscaped, however I have one small section of grass for my dogs. I'm not sure I agree on which is cheaper to water. My grass takes 25 minutes of watering twice a week. My roses take 3 hours of watering (drip irrigation) three times a week. I suppose because I have more roses than I have grass, that is what makes it take so much more water to water my 250+ roses. but roses do drink lots of water out here, I'm sure to make up for all the moisture they loose through their foliage. At one time I had over 425 roses.