Leaves provide a blanket of cover for overwintering perennials, and essential habitat for pollinators and other wildlife.
Embrace the mess.
As autumn's brilliant colours fade and leaves blanket our gardens, many homeowners instinctively reach for rakes and leaf blowers, eager to restore their lawns to a pristine green carpet. However, this well-intentioned tidiness comes at a significant cost to the wildlife that depends on leaf litter for survival through the harsh winter months.
By leaving the leaves where they fall, you can provide crucial habitat for insects, invertebrates and mammals while supporting the entire ecosystem that sustains local biodiversity.
For insects, fallen leaves represent nothing less than a lifeline through winter. Countless butterfly and moth species spend the cold months nestled within leaf litter in various life stages.
Some overwinter as eggs attached to dried leaves, while others shelter as pupae or chrysalises tucked beneath the protective layer. Native bees, which are early, more effective pollinators than honeybees for many plants, also depend on leaf cover.
These solitary bees often nest in small cavities within the soil, and the insulating layer of leaves above provides essential protection from temperature extremes that could otherwise prove fatal.
Ladybugs, ground beetles and other beneficial predatory insects seek refuge under leaves during winter, emerging in spring to control garden pests naturally. By removing leaves, we eliminate these allies and potentially create a need for chemical interventions that further harm the ecosystem.
Beyond insects, a diverse community of invertebrates thrives within decomposing leaf litter. Earthworms, nature's premier soil engineers, pull leaves underground where they break them down into nutrient-rich castings that improve soil structure and fertility.
Millipedes, sowbugs and pillbugs process fallen leaves into organic matter, releasing nutrients back into the soil for plants to use. These "decomposers" are fundamental to healthy ecosystems, yet they require the very leaf litter that many gardeners discard.
Spiders, including species that help control mosquito populations, also overwinter in leaf piles, maintaining vital pest control services.
The benefits extend upward through the food web to mammals that depend on the insects and invertebrates living within leaf litter.
Shrews, among the world's tiniest mammals, maintain incredibly high metabolisms and must eat constantly to survive. They hunt through leaf litter for insects and invertebrates, and without the habitat, their winter food supply vanishes.
Chipmunks and other small rodents also forage through leaves for seeds and nuts while hunting for the insects that supplement their diets.
Those small mammals, in turn, support larger predators like foxes, owls and hawks, demonstrating how leaf litter influences the entire food chain.
For birds, leaf litter provides essential foraging habitat, especially during migration and winter when food sources become scarce.
Countless species scratch through leaves searching for insects, seeds and other food items. By maintaining leaf litter, we support both resident birds through winter and migrating species that depend on refuelling stops during their long journeys.
The ecological benefits of leaving leaves extend beyond wildlife support. As leaves decompose, they create a natural mulch that suppresses weeds, retains soil moisture, and moderates soil temperature.
This free, renewable resource reduces the need for synthetic fertilizers while improving soil health organically.
The practice also saves homeowners time, money and physical effort while reducing noise pollution and fossil fuel consumption from leaf blowers and such.
Rather than viewing fallen leaves as yard waste requiring removal, they should be recognized as a valuable resource that supports biodiversity and ecosystem health.
For those concerned about aesthetics, leaves can be mulched with a mower and left on lawns, where they'll decompose quickly, or moved to garden beds where they provide all the benefits described while maintaining a tidy appearance.
The simple act of leaving the leaves represents one of the easiest and most effective ways Okanagan gardeners can support wildlife and contribute to environmental conservation right in their own backyards.
Geared to those who can't stand a messy garden, a future column will discuss the benefits of cleaning up some specific leaf litter.
Visit the Okanagan Xeriscape Association's website at okanaganxeriscape.org to learn more about best practices in your garden.
The Okanagan Xeriscape Association is grateful for the ongoing financial support of the Okanagan Basin Water Board and is proud to be collaborating on the Make Water Work campaign. Check out the Make Water Work plant list at makewaterwork.ca.
This article is written by or on behalf of an outsourced columnist and does not necessarily reflect the views of Castanet.