Not all mulch is equal. The wrong choice can starve your plants of nitrogen, attract termites, or wash away in the first storm. Picking the best mulch for your garden starts with understanding how each type breaks down, how long it lasts, and what it does to soil chemistry.

Organic vs inorganic

Organic mulches (wood, bark, straw, leaves) decompose — they feed soil microbes and improve structure over time. Downsides: need annual topping up, some tie up nitrogen as they decay, can harbor pests.

Inorganic mulches (stone, rubber, landscape fabric) don't decompose. They last for decades with minimal maintenance — but don't improve soil, can transfer heat to plants, and many are difficult to remove if you change your mind.

Hardwood mulch

The default choice in most of the US. Made from chipped hardwood trees (often municipal waste).

  • Pros: Inexpensive ($25-$40/yd bulk), widely available, decomposes to enrich soil, moderate lifespan (12-18 months of full color)
  • Cons: Ties up nitrogen at soil surface as it decays, fades to gray, can float in heavy rain
  • Best for: Ornamental beds, shrub beds, pathways

Cedar mulch

Made from western red cedar or northern white cedar. Natural oils repel some insects.

  • Pros: Natural pest repellent (termites, moths, some ants), pleasant aroma, slower decomposition (18-24 months), holds color longer
  • Cons: Expensive ($40-$60/yd), aromatic oils can slow seed germination if sown directly
  • Best for: Near foundations, children's play areas, paths, insect-sensitive plantings

Pine bark and pine straw

Pine bark comes in nuggets (large) or shreds (small). Pine straw is long pine needles, typically sold in bales.

  • Pros: Pine straw is very light and doesn't wash away on slopes; pine bark is slow-decomposing; both slightly acidify soil
  • Cons: Pine straw needs replacement every year; pine nuggets float in heavy rain
  • Best for: Pine straw — slopes, azaleas, rhododendrons, blueberries. Pine bark — decorative beds, orchid/acid-loving plants.

Dyed mulch

Usually hardwood mulch colored with iron oxide (brown, red) or carbon black (black). Modern dyes are non-toxic.

  • Pros: Color holds 12-18 months, curb appeal, often cheapest by volume
  • Cons: Some dyed mulches are made from ground pallets and construction debris — may contain chromated copper arsenate (CCA) or other chemicals. Buy from reputable suppliers only.
  • Best for: Ornamental beds where visual appearance matters most

Cocoa bean mulch

Hulls from cocoa bean processing. Chocolate-like smell (for a few days).

  • Pros: Lightweight, attractive, breaks down into rich organic matter, repels some garden pests
  • Cons: Expensive ($50-$80/yd or $8-$15 per 2-cu-ft bag), TOXIC TO DOGS if eaten (contains theobromine), can grow mold in humid weather
  • Best for: No-dog households, high-visibility small beds

Rubber mulch

Recycled tire rubber, usually dyed.

  • Pros: Extremely long-lasting (10+ years), excellent for playgrounds (shock-absorbent), doesn't wash away, doesn't decompose
  • Cons: Doesn't improve soil, gets hot in direct sun (150°F+ surface temp), can leach zinc and other metals, flammable, impossible to remove if you change your mind
  • Best for: Commercial playgrounds, dog runs, high-traffic areas where plant health doesn't matter

Stone and gravel mulch

River rock, lava rock, pea gravel, decomposed granite.

  • Pros: Permanent, low maintenance, good drainage, fire-resistant, doesn't blow away
  • Cons: Reflects heat back onto plants (stresses them), doesn't improve soil, weeds seed easily into crevices, very heavy to install or remove
  • Best for: Xeriscapes, cactus gardens, fire-prone areas (California, western US), drainage areas

Leaf mulch and compost

Shredded leaves or finished compost used as mulch.

  • Pros: Free (if you have leaves), extremely rich in nutrients, improves soil dramatically, works well for vegetable gardens
  • Cons: Decomposes fast (4-6 months), doesn't look as "neat," fine compost can form crust
  • Best for: Vegetable gardens, natural-style beds, under trees (mimics forest floor)

What to avoid

  • Fresh wood chips near newly planted shrubs — ties up nitrogen
  • Dyed mulch from unknown source — may contain ground treated pallets
  • Cocoa mulch if you have dogs
  • Rubber mulch around food crops
  • Any mulch piled against tree trunks ("volcano mulching") — causes rot and pest entry

Application tips

  1. Weed first. Mulch suppresses but doesn't kill established weeds.
  2. Keep 3-6 inches clear from the base of tree trunks and woody stems.
  3. Water before and after — mulch is harder to apply when beds are dry.
  4. Don't overdo it — 3 inches is enough. 6 inches smothers roots.
  5. Refresh, don't replace — add an inch annually rather than removing and starting over.

Calculate what you need

Once you've picked a mulch type, use our mulch calculator to convert your bed dimensions and target depth into cubic yards or bag count for your project.