The Best Mulch for Flower Beds and Gardens

Shredded Hardwood: The Default Winner

Shredded hardwood is the most-used mulch in America for a reason. It interlocks so it stays put on slopes, breaks down slowly, feeds the soil, and looks tidy. It is my default for flower beds around foundation plantings.

Choose a natural (undyed) product when possible; the black and red dyed mulches often use recycled construction lumber that can contain contaminants.

Pine or Fir Bark Nuggets

Large bark nuggets look great around trees and shrubs and last two to three years. They float, though, so avoid them on slopes or where water runs across the bed.

Pine Straw

A Southern favorite for a good reason: it is light, easy to spread, breathable, and slightly acidifies soil, which flowering shrubs like azaleas and camellias love. Refresh yearly.

Arborist Wood Chips

Free from tree services in most cities and excellent around fruit trees and mature perennial beds. Chips are coarser and take longer to break down than shredded mulch, so keep them away from tender annuals until they mellow for a season.

Do not till fresh chips into soil; they temporarily rob nitrogen. On the surface, they are ideal.

Shredded Leaves

The best free mulch you can get. Run the mower over fall leaves and pile them two to three inches deep in beds. Earthworms will pull them into the soil by spring, adding organic matter you would otherwise pay for.

Straw (Not Hay)

Straw is the vegetable garden staple. It is clean, light, and easy to move as you rotate crops. Buy straw, not hay; hay carries weed seeds.

Also watch out for straw sprayed with persistent herbicides; ask the supplier before buying by the bale.

Rubber Mulch: Skip It in Gardens

Rubber mulch has a place under playground equipment but not in your garden. It does not feed the soil, retains too much heat, and can leach zinc and other compounds as it degrades.

How Much Mulch to Apply

Two to three inches is the sweet spot for most mulches around perennials and shrubs. One and a half to two inches is enough for annuals and vegetables where you replant often. Deeper than four inches starts to smother roots and repel water.

A cubic yard of mulch covers roughly 100 square feet at three inches thick.

Never 'Volcano Mulch' Trees

Piling mulch against a tree trunk traps moisture, invites rodents, and rots bark. Instead, spread mulch in a wide flat 'donut' out to the drip line, keeping the mulch pulled back 3 to 4 inches from the trunk.