Photo Karen Graham. The Nature Conservancy of Canada suggests we save our backs and contribute to the protection of our biodiversity by leaving the leaves on our lawns. In Cavan-Monaghan, leaf and brush debris is now redirected to a local farm where it is composted and used as a soil amendment, which is another environmentally responsible use of this valuable debris.
The Nature Conservancy of Canada has launched a public awareness campaign asking people, in order to preserve, protect and enhance our quickly vanishing biodiversity, to not rake up leaves on lawns. It’s not clear why we seem to get this ingrained notion, almost an obsession that our lawns need to be fully bare and exposed for the winter with very single fallen leaf needing to be bagged, disposed of and hauled away. Renowned British horticulturalist Monty Don has speculated in his TV series that the North American need for weed and leaf free lawns might have originated in in pioneer times where Nature was viewed as the enemy to be vanquished at all costs. This compulsion for neatness could also reside in the fact that many lawns, especially urban lawns across Southern Ontario, are comprised of cool season grasses such as Kentucky blue grass which revitalize themselves in the fall and strengthen their root systems. A thick layer of leaves can deprive the grass of the one element they require to do this – sunlight.
However, the ‘lawns’ of many a rural property contain little Kentucky blue grass, but rather an assortment of other grasses and ‘other plants’. Leaf cover helps native insects, including pollinators and other backyard wildlife, hibernate through the winter. Fallen leaves provide homes for various butterfly and moth larvae to overwinter as pupae. Toads, shrews and salamanders benefit from leaf litter to hide as well as hunt. If leaf piles seem too dense and thick, they can be carefully run over with a mower into smaller pieces that will decompose faster. On the other hand, a thick layer of fallen pine needles can produce a thick mat that forms a physical barrier, either retarding grass growth or killing it entirely. But a thick layer of pine needles, which are slow to decompose, arguably make an attractive groundcover and creates an area that one no longer needs to mow.
But if one wants a bare lawn, consider raking leaves onto garden beds. Fallen leaves, aside from benefitting a variety of wildlife, also provide winter insulation thus protecting perennials, especially tender ones. Leaf cover also protects perennials from being subject to the often deadly freeze-thaw spring cycles. The leaves then break down in the spring and summer providing important nutrients for plants. Concerns have been raised about certain leaves being toxic. There are two large black walnut trees here in the Moraine garden that shed their leaves onto a garden bed without any sign of harm. That’s because the juglone toxin in walnut leaves breaks down when exposed to air, water and bacteria. They can even be composted.
Leaves are often collected for regional composting programs. In Cavan-Monaghan Township a proposal by the operators of Woodleigh Farms to accept leaves collected by the township to be used as a soil amendment on their 500 acre farm has recently been approved.
By Jane Zednik, Millbrook and Area Garden Club
Reprinted with permission from the October 12th edition of the Millbrook Garden Club newsletter, Gossip and Glee. While meetings of the Garden Club are currently cancelled, its members continue to educate and entertain on garden-related topics through their website and electronic newsletter. Visit www.millbrookgardenclub.ca to sign up for the newsletter or ask a garden-related question of our many local garden experts who will be happy to share their knowledge. KG