What is the difference between bark mulch and wood chips

Bark mulch and wood chips share a woody origin yet behave differently once they meet the garden. Bark mulch is stripped from the outer layer of trees, usually pine, spruce or hardwoods. Its structure runs fibrous and layered, rich in tannins and natural waxes that slow decay. Spread five centimetres thick, bark settles into a knit that blocks sunlight and smothers weed seedlings, while still letting rain filter through. Because decomposition is gradual, top-ups are needed only every couple of seasons, and the slight acidity supports camellias, heathers and blueberries.

Wood chips, by contrast, comprise inner sapwood and sometimes small twigs, sliced mechanically from pruned branches or sawmill off-cuts. Their chunky pieces decompose faster, releasing nutrients and lifting soil humus more quickly than bark. The chips absorb water, making paths safer but demanding more frequent renewal if used as mulch. Sapwood’s higher nitrogen draw can temporarily steal fertility from nearby seedlings, so a sprinkling of well-rotted compost balances the ledger.

In design terms bark offers a dark blanket, whereas chips lend a woodland feel. Selecting between them depends on desired appearance, breakdown speed and plant palette. AHS LTD supplies both materials, enabling gardeners to match mulch choice precisely to purpose.