There are many different types of mulch materials that make good garden covers. Many mulches can be purchased in bags or delivered in bulk. Some can even be obtained for free.
List of Natural Mulch Options
1. Wood Chips and Bark
Wood chips and bark are among the mulches most commonly used in landscaping. Woods such as cedar, cypress, and pine are popular because they are durable, look good, and smell great. Larger pieces of wood or bark don't break down as quickly as shredded wood mulches, but may float away in heavy rain. Shredded mulch is especially useful on slopes or paths, because it doesn't easily wash away. Wood chip and bark mulches can be purchased at garden centers and sometimes it can be obtained free of charge. Road workers generally shred the overhanging branches they remove from roadsides into coarse mulch, and often they will give the mulch away. There is always some possibility that the original trees were diseased, but many gardeners have used this free mulch for years with no difficulties.
2. Cypress Mulch
Cypress is one of the most popular mulches used in gardens today. However, if you choose it, be sure to ask your supplier about the source of the mulch. The demand for cypress mulch has led to clear cutting many cypress swamps, especially in Florida and Louisiana. This changes the wetlands so severely that they can no longer fulfill their natural function of absorbing hurricane floodwaters.
Because it's not very ornamental, straw is best used in vegetable gardens or over newly seeded lawns. It works well in vegetable gardens because it improves the soil as it decays, and makes walking around the garden easier in the meantime. Straw is also a good material to use as winter mulch for perennials. Be careful not to use hay or straw that contains too much weed seed or you'll have a garden full of weeds in the spring.
4. Pine Needles
A two-inch layer of pine needles makes an excellent, attractive mulch for acid-loving trees and shrubs.
5. Cocoa Bean Hulls
Many gardeners use cocoa bean hulls as a mulch. They are a beautiful color and have an attractive fragrance. However, cocoa bean mulch should be avoided if pets are allowed in the area. It contains theobromine, which is highly toxic to dogs and cats. Many dogs are attracted to cocoa bean hulls, and the result can be deadly. You can read more about it at the ASPCA.
6. Other Organic Mulch Materials
Compost or shredded leaves are excellent types of mulch for gardens because they add nutrients to the soil as they break down. They're also readily available. After the leaves decompose, dig them into the soil and add a new layer on top. Grass clippings can be left on your lawn or used to mulch vegetable or flower gardens. However, you shouldn't use clippings from lawns that were treated with herbicides.
Landscape rocks are available in many sizes, shapes and colors. Rocks don't do anything for the soil nutritionally, but a one- or two-inch layer will help suppress weeds. Rocks are hard to get rid of once you have them, so they are best used for permanent plantings. Rocks reflect solar radiation and can create a hot landscape during the summer months. They look good in desert or xeriscape gardens.
List of Non-Organic Mulching Options
1. Black Plastic
Black plastic is very effective in preventing weed growth. Because it also holds water in the soil, it is not recommended for poorly drained areas. Black plastic does a good job of warming soil up in the spring, so you can get an early start on planting tomatoes and other vegetables that like warm soil. To disguise its ugliness and reduce heat absorption, cover black plastic with a layer of bark.
2. Landscape Fabric
Materials woven of fabric, plastic or paper are available at garden centers and often types of mulch used by professional landscapers. These materials are treated to resist decomposition, but unlike black plastic, the fabrics allow water and air to move through them.
Landscape fabric needs to be fastened down with pins so it will not be pushed up by perennial weeds. You will want to cover the fabric with a few inches of another mulching material such as wood chips, both to hide the fabric and because it is possible for weeds to sprout up on top of the fabric. Landscape fabric is best used for more permanent plantings because it is more difficult to transplant plants that are growing in fabric.
Believe it or not, newspaper makes an excellent type of mulch. Use it to smother weeds around perennials and shrubs. Apply a heavy layer of natural mulch such as wood chips on top to hide the newspaper and keep it from blowing away. Newspaper is better than plastic, because it will eventually decompose. Don't use glossy paper in vegetable gardens, because the ink could leach into the soil.
Visit Your Garden Center
Before you decide which type of mulch you want to use, visit your local garden center to see all of your options. One type of mulch is bound to appeal more to you than the others, and this will help you tailor your landscape to look just the way you want it to.