Mulch Depth Guide
How deep to mulch different plants, and why more is not always better for tree and shrub health.
2 to 3 inches for annual and perennial beds, 3 to 4 inches for shrub and tree rings. Keep mulch pulled back 2 to 4 inches from tree trunks and stems to avoid rot and volcano-mulching damage.
Bed and border depths
Annuals and perennials do well with 2 to 3 inches of mulch. Deeper than 3 inches can hold moisture against stems and encourage disease.
Trees and shrubs
Aim for 3 to 4 inches in a wide ring extending out to the drip line. Keep the base of the trunk clear. Volcano-mulching (piling mulch against the trunk) traps moisture and invites decay.
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Use the mulch calculator to get a specific quantity for your project.
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Sources
Last reviewed . Educational estimates only; local conditions and codes take precedence. Consult a qualified professional for site-specific decisions.