Better mulch isn’t about convenience. It’s about ecology. The best mulch for your trees is a load of mixed arborist chips from a local tree service.

Material. A forest floor is not uniform—it’s a complex mix of leaves, twigs, bark, fungi, and decaying wood. Bagged mulch is usually a simplified byproduct of that system, often just bark or ground wood from mills. It’s missing the full diversity of materials that feed a complex soil food web. Trees don’t grow in sterilized wood chips—they grow in place, in place-based materials, shaped by centuries of local decay and renewal. 

Plastic. No matter how it’s marketed, those bags don’t just disappear. “Compostable” claims sound comforting, but compostable in what system, under what conditions, and in what timeframe? Most of these bags still end up in landfills, slowly breaking down—or not breaking down at all—into yet another layer of plastic in the environment.

Carbon footprint. Every bag of mulch has a story of diesel trucks, processing facilities, and long-distance shipping. That bag of mulch might have traveled farther than you did this month. And somewhere along the way, forest materials were stripped, processed, and moved instead of being left where they naturally belong: on the forest floor.

Size. Uniform particles behave uniformly—and that’s part of the problem. Real forest mulch is heterogeneous, creating different decomposition rates and habitat niches for fungi, bacteria, and soil fauna. Overly fine or uniform mulch can compact, limit airflow, and skew soil biology toward a simplified system instead of a diverse one.

Dyes. Colored mulch may look tidy, but those dyes often come with additives designed to slow breakdown. But breakdown is the point. Trees don’t need decoration—they need carbon cycling, fungal colonization, and steady organic matter turnover. Anything that slows that process works against the system you’re trying to support.

Excess. More mulch is not always better. Thick layers greater than 4 inches can suffocate gas exchange and trap moisture in ways that stress roots rather than support them. If last year’s mulch is still intact, nature is telling you something. Leaves, branches, and time are already doing the work—often better than we can replicate.