There is a week in June when Littleton's cottonwoods let go and the seed drifts down the street like snow that forgot the date. Eco Joe Lawn Care is out in it, cutting grass, trimming borders and edging walks through the long green stretch of a Colorado summer, when lawns grow hard in the mornings and hold their breath through the bright afternoons. Water is a considered thing in this valley, and grass cut at the right height keeps more of what it is given. The finished yard has that clean-shaven look that makes a whole block sit up straighter. Then the mower moves on, and the sprinklers tick back to life behind it.