Gardening at 8,700 feet is mostly a matter of timing. Silverthorne beds wake late and then rush all at once — aspen leafing out on the slopes above Salt Lick, lupine and paintbrush going off in a matter of days — and Alpine Gardens works to that clock, mowing, edging, cutting back and clearing winter's litter out of the plantings so none of the short season is wasted. Turf up here wants attention in the cool of the morning, before the sun turns sharp. By July a well-kept mountain lawn holds its green against the dark pines like something painted in. Then the work turns to putting it all down gently again for the cold.