It is mid November in Southwestern Ontario and wild bees and butterflies have mostly gone into hibernation or some sort of winter rest. For those of us who love spending our days surrounded by pollinators this may seem like a sad time but there are several important things you can do now in order to create the conditions for bee and butterfly abundance and flourishing in the spring.
The most important thing you can do is nothing, or next to nothing! Yes, being a lazy fall gardener is a great thing for wild bees and butterflies. Specifically, leave the leaves that fall on the ground right where they are. If they fall onto a deck or sidewalk, gather them up gently and put them on a garden bed. People often ask if leaving leaves will ruin lawns. This is hard for me to honestly answer in a satisfying way to the person asking the question (Just like the question: How do I get rid of carpenter bees?). A thick layer of leaves may damage your lawn and good, because but who wants a lawn anyway? (that’s my honest answer). But usually I just assure them that a thin layer of leaves will not damage lawns, which is also the truth. The excess leaves can be gently! placed on a garden bed or under a tree.
Why should you leave the leaves? Most butterflies in the northern hemisphere do not migrate to tropical areas like the Monarch Butterfly but instead hibernate in the same region in which they live the rest of their life. Butterflies overwinter in various forms depending on species but many utilize dead leaves in their hibernation. Curled up in the dead leaves on your grass may be the eggs or chrysalis of a butterfly (moths also utilize dead leaves). If you throw your leaves in a bag to be composted in an industrial municipal composter or mow over them, you will kill these critters. Additionally, many native bees overwinter in the ground, including mated bumblebee queens, and they also like a thin layer of leaf mulch as insulation and protection. In fact, they probably partly chose their winter home based on the presence of some dead leaves.
Another lazy fall action you can do (or, more accurately, not do) is to leave the stems of dead perennials standing in place. Do not trim them down to the ground. Many species of wild bees, and other insects, nest in those stems. Throwing them in a compost heap or gathering them up to send to the municipality will likely kill them. If you leave a few seed heads, you may also help winter birds find food and you add interest to the winter landscape. If you must cut your stems, bundle them and stand them upright. This will give the bees a chance to survive the winter and emerge in the spring. I do pull out and compost annual vegetable stems, although some vegetables we think of as annuals such as almost all Brassicas (broccoli, kale, etc) will live through the winter (at least here in climate zone 6b) and will flower in the late spring, providing nectar for butterflies and bees.
One task I do in the fall for pollinators is planting bulbs of early spring flowers. The more diversity of food provided for pollinators when they emerge in the spring, the better. Fall is also a great time to scatter seeds of native plants that need a deep freeze followed by a wet thaw in order to germinate.
I know that leaving leaves and dead stems may upset your neighbours. Some people are very attached to their lawns, in ways they may not fully understand (see my article on lawns, class, and colonialism). For some people a well-maintained lawn, which includes raking up and disposing of dead leaves, is part of what it means to them to be neighbourly and even to be a “good” citizen. I recommend explaining to your neighbours why you are leaving the leaves. You can contextualize your actions within the global crisis facing insects and can mention how seemingly small actions, like adjusting some gardening practices, can make a difference for local species of insects. I find that people generally have positive feelings about butterflies and bees but little knowledge. Let them know about the many species of butterflies that hibernate in your region and about the native bees that nest and winter in hollow stems and the ground. If your neighbours have children or grandchildren, I recommend recruiting them to spread your message. Children, I find, feel an affinity for non-human animals of all kinds. It is easier to inspire a sense of awe and wonder about nature in children than in adults.
These actions may seem small and insignificant but the beauty of insects is that small actions can have a large impact, especially in an urban setting that is a distance from rural landscapes that may be dominated by industrial agriculture. You can do things in your outdoor spaces that have a positive impact on the bees, butterflies, and other insects in your area. You will be thanking yourself in the spring when you, if you’re lucky, get a glimpse or hear the buzz of some of those emerging critters you helped to survive the winter.