Gardeners mean well, but the act of gardening can be a hindrance to increasing biodiversity. Maybe, says Rebecca McMackin, we need to let leaves be. Illustration Rosanna Morris <\/p>
Piet Oudolf <\/a>once told me: \u201cAmericans like to display their mulch.\u201d He\u2019s not wrong, sadly.<\/p> Mulch<\/a> is part of our garden aesthetic. Is it a lack of imagination? A nefarious scheme to lower the required training of landscape staff? Whatever the reason, I\u2019m so grateful it\u2019s changing.<\/p> Gardeners all over the world are developing strategies to encourage biodiversity<\/a> in our landscapes. The rewilding<\/a> movement is spreading and naturalistic gardens <\/a>are seeding in everywhere. But even people who prefer more formal or floral gardens can incorporate practices that invite in wildlife<\/a>. A big part of that work starts with mulch, leaves and soil<\/a>.<\/p> The very top of the ground, where leaf litter breaks down into humus, is an incredibly rich ecological zone that gardeners often unknowingly remove. That zone, the \u2018duff layer\u2019 in ecological parlance, is necessary habitat for many of the animals we love, as well as one of the main techniques that plants Gardeners like to garden. But wildlife tends to thrive in areas we leave alone<\/p> <\/blockquote> In autumn<\/a>, when tree leaves fall to the ground, they aren\u2019t being thrown away. Trees are carefully placing those leaves over their root systems where they insulate the soil and hold in moisture. Worms will pull leaves deep into the ground where carbon is sequestered. Fungi and bacteria will break them down until micronutrients are cycled back into plant-available forms. As leaves, twigs and other plant materials biodegrade, they create the soils that those trees prefer. It\u2019s terraforming. Some gardeners have it backwards: we\u2019re not making soil for plants \u2013 the plants are making it for themselves.<\/p> Many animals have come to rely on that duff layer. Bumblebees will overwinter just underneath those leaves, in the soft soils of northern slopes. Many moths and even a few butterflies<\/a> spend part Insects such as beetles and woodlice who play critical roles in larger food webs often rely on the structural complexity of that leaf layer to hunt and hide. When we make more habitat for insects, we invite the birds<\/a> who rely on them into the garden as well.<\/p> None of this is to say you should let leaves smother your lawns<\/p> <\/blockquote>