Green leaves are the energy engines that fuel our gardens. Without them there would be no flowers, no sugars for summer tomatoes, and no cooling or oxygenating the air while growing the mighty trees that give landscapes a sense of time and permanence. A gardener’s admiration of leaves can quickly fade, however, when faced with brown leaves blanketing everything from azaleas to annuals, and patios to pools. Leaves are suddenly a problem, something to manage—in other words, work.