Mulches provide moisture retention and insulation, prevent weed growth and limit soil erosion. Bulk mulch is available in bark, hardwood, rubber, stone and organic varieties. Several factors to consider when choosing the best mulch are function, cost, and quality. Mulch materials, colors and size vary, so there also is room to choose based on personal taste.
Both bark and hardwood mulch are ideal choices for shrub and flower beds. Bark mulch is made of shredded bark and is often sold in bags largely intended for homeowners. Bark and hardwood bulk mulch may be colored and chemically treated or organic. Shredded mulch produced from roadside clearings is sometimes available free of charge from municipalities.
Hardwood mulch is made of a combination of the bark and hardwood parts of the tree. Varieties include maple, oak, cherry, birch and cedar. The size of the wood chips varies. The more the wood is shredded, the finer the chip. Finer mulch inhibits weeds more effectively, but larger chips and bark do not decompose as rapidly.
Organic, untreated mulches are especially useful in vegetable gardens because they improve the quality of the soil by adding nutrients without adding unwanted chemicals. Natural mulches include pine mulch, or pine straw, which forms a mat ground cover that is especially rain resistant. Other natural mulches include shredded bark and hardwood materials. Organic mulch lasts up to three years before decomposing but turns gray relatively quickly.
Often made from ground, recycled tires, rubber mulch is non-toxic, does not attract insects and does not decompose. Playground mulch made from recycled tires or other rubber material is effective in reducing playground injuries. While the initial cost of rubber mulch is more expensive than wood mulches, it is much more durable and, therefore, less maintenance is required.
Stone mulch also has the added advantage of no decomposition. Less maintenance is required, though stone also is initially more expensive than wood mulch. Stone is decorative, available in a wide variety of colors, and efficient in preventing weed growth.
Use from 3 inches to 4 inches (7.6 cm–10 cm) of mulch on flower and shrub beds for proper weed control. At this thickness, 1 cubic yard of mulch (0.76455 m3) covers 100 square feet (about 9.3 m2) of landscape. For playgrounds, 4 inches (10 cm) of mulch is recommended for optimal safety.
Both quality and pricing across bulk mulch suppliers vary but, as with anything else, a trade-off exists between price and quality. Bark and hardwood mulches are generally less expensive than rubber and stone. Bulk mulch is available from local garden supply and landscape companies. It may be processed or sold without screening or grinding.