Winter 2025

Messy is Good for the Planet

by Pamela Austin

"Every leaf speaks bliss to me, fluttering from the autumn tree." - Emily Brontë

Good news! Skipping your garden clean-up and leaving your garden “messy” can have remarkable benefits for insects, birds, and plants in your garden. Instead of reaching for the rake and blower, consider leaving the leaves.

The leaves that drop in the fall are an asset to your garden, they are helpful to insects, pollinators, invertebrates, microorganisms, and the soil.

Fallen leaves contain fifty to seventy percent of the nutrients that trees have absorbed from the earth. Why let all those valuable nutrients be hauled away? Leaves are truly a gift to gardeners—so why not put them right back to work in your landscape?

These are the ways fallen leaves benefit wildlife.

Habitat

Your garden can help fill the need for habitat and food that has been lost due to urban development.

Leaves, fallen branches, flower stems, and dried seed pods provide a habitat for insects and invertebrates. The availability of overwintering habitat is crucial in determining the survival and population levels of native bees and beneficial insects. It can also provide abundant food for songbirds, butterflies, wasps, moths, fireflies, and ground beetles. Salamanders find protection from predators and weather in leaf litter and brush piles that help the soil remain moist. Butterflies lay their eggs on fallen leaves, while hollow-cut stems offer refuge to insect larvae, pupae, or overwintering adults. Many of these insects are essential pollinators and come spring, they will be beneficial to your garden flowers. Caterpillars that hatch in the spring provide food for baby birds.

If you must tidy up your yard, gently move leaves to garden beds or around the base of trees.

Compost

Leaves provide a natural compost. Through the winter they decompose, feeding and conditioning the soil as nature intended.

Leaf mold is a soil amendment made from decomposed leaves of deciduous trees and shrubs. It is a fungal-driven decomposition process. It improves soil structure, making it easier for plant roots to access oxygen, water, and nutrients. Leaf mold is created by allowing leaves to decompose on their own, without other organic matter.

Natural “composters” such as millipedes and worms break down organic matter, in this case, fallen leaves, into its basic elements, enriching the soil. Additionally, composting boosts the activity of earthworms and other natural soil organisms that promote plant growth. These organisms surface to feed and then return to the soil, where they continue to nourish plants in the spring.

Although low in essential nitrogen, fallen leaves still contain small amounts of all the nutrients plants need and are a valuable source of soil-improving organic matter like calcium, magnesium, nitrogen, and phosphorus.

Pound for pound, the leaves of most trees contain twice as many minerals as manure. For example, the mineral content of a sugar maple leaf is over five percent and even common pine needles have two and a half percent of their weight in calcium, magnesium, nitrogen, and phosphorus, along with other trace elements.

Sending leaves to the landfill is a waste of valuable natural resources. By composting leaves instead, we can recycle these organic materials back into the environment.

Mulch

Using the leaves that fall in your garden can save you from buying mulch. Mulching suppresses weeds, retains moisture, and boosts nutrition. Roughly 70% of native bees nest in bare soil, such as digger bees and mining bees, which create burrows in exposed, sandy, or well-drained areas. Other native bees, like bumblebees, often prefer dense vegetation, where they can nest in abandoned rodent burrows or among thick grass and plant roots.

Mulch can protect the roots of your plants from the cold and shade the soil to keep plant roots cooler. Two to four inches of mulch is all you need.

Leave the leaves as they are. It isn’t necessary to chop them up in the fall as this practice risks destroying habitat for insects and eggs.

Conclusion

Leaving fallen leaves in your garden offers a wealth of benefits, including habitat for wildlife, natural compost, and free mulch.

By supporting nature’s ecosystem, you're helping both wildlife and human communities thrive. So, sit back, relax, and let nature work its magic in your garden.

Resources

Xerces Society

Turn Fallen Leaves into Compost
University of California Agriculture and Natural Resources
https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=29186

Leave the Leaves to Help Pollinators
https://campusgrown.ucdavis.edu/blog/leave-leaves-help-pollinators

Permission to Leave the Leaves
https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=60894