Autumn clean ups for your customers used to be a clear and distinct process. Roll in, final mow, prune and pick up, and maybe, budgeting allowing and customers willing, divide some perennials and build more garden spaces with their own plants.

Now there’s more research, a different baseline of understanding, and even more opinions about this to be found on the internet. One end of the spectrum on this topic is represented by organizations such as the Xerces Society with their campaign “Leave the Leaves.” In this marketing blitz, we are learning the importance of leaving the leaf litter for the butterflies, for instance, overwintering here, as caterpillars huddled and bundled in rolled up leaves for warmth and protection from predators. The Luna Moths we’re so fascinated with, with their dramatic wingspans and short, interesting life cycles in June, disguise their cocoons and chrysalis as dried up leaves.

When we rake up, mow, and mulch, or worst of all by some standards, use a leaf blower to corral fallen leaves, we are destroying the next generation of many, many pollinators that would have emerged in the spring and started their beneficial work for another life cycle. When you see some of the fritillary butterflies, for instance, in the spring, it’s because they were able to survive all winter, in some of the leaves left undisturbed whether in a forest, thicket, or some gardeners’ lawns who are aware of the “Leave the Leaves” knowledge and movement.

Leaving leaf litter provides habitat for many types of bees and wasps along with all the beneficial insects overwintering. More and more research is indicating that these populations are dwindling, but are essential for our food supply. If your customers are adverse to leaving the leaves and how their yards and gardens will look quite different from crisp and clean (or barren and bewildering, in some viewpoints), then the next best thing would be to gather the leaves and spent perennial material and make a corner area on the property to house that material, giving the eggs and larvae in there the opportunity to overwinter and emerge in the spring.

Another benefit to leaving the leaves, whole, and not shredded, can be to use as mulch. We see a lot of research about the whole leaves actually doing a better job of mulching than the same material shredded. The whole leaves serve to retain moisture and, as whole leaves, provide a stronger weed mat by helping suppress sunlight which helps germinate those pesky weed seeds. The Xerces Society blog, written by Justin Wheeler, points out what I found to be one of the most compelling aspects of leaving whole leaves that I have read from any source. He reminds us that when we are appreciating the spring ephemerals, we often see their “delicate” stems poking up through a leaf, or their stems weaseling through a pile of leaves. The spring ephemerals are strong, forceful, and dynamic and not dissuaded by a few leaves piled smoothly on top of their growth flight plan.

Other professional sources with interest in lawn care expertise, see many other aspects of this situation. Leaf litter for landscapers can also present other problems to weigh against the environmental focus.

One consideration of landcare professionals is the way a mat of leaves can prevent rain water from reaching to the grass roots or plant roots. Young grass may not grow in evenly, depending on the layer of leaf cover they are working against. This prevents a lush, verdant lawn many of your customers want to maintain. By removing the leaves, there will be even distribution of sunlight, water, and various fertilizers you may be using by your own preference or by your customers’ requests. A full, traditional fall clean up will result in that “look” they may be striving for.

Leaf clean up should mean there is as little disturbance as possible for the insects already mentioned overwintering in what you may have cleaned up and, in previous years, thrown into a landfill. An autumn clean up will definitely remove the places deleterious pests and mold will thrive. Check with your Cooperative Extension service or where you have a working relationship with lawn care products, to learn about the ways snow mold hatches and spreads. Learning about the molds and diseases of turf grasses, such as brown patch, will help you determine risk management about autumn clean ups in your area.

Leaving some leaves while thoroughly clearing out others seems to be a reasonable compromise as we learn more and educate clients more, about the “Leave the Leaves” and similar movements. Perhaps leaving leaves in areas where you are going to design in a pleasing garden pathway is a meaningful, beneficial and economical way to begin that process.

It’s all about education, and about learning how we fit in to the natural world. Considering helping your clients diminish the area of expansive, monoculture lawn area by removing some grass and planting some native shrubbery or perennials will be a great way to start the conversation and conversion to healthy lawns living side-by-side with habitats conducive to wildlife, including our much-needed pollinators.

—by Cris Blackstone, NHCLP