Red cedar mulch is a wood mulch made from red cedar trees and is used mainly for a garden cover. It is available in small chunks, shredded or ground, and is spread in a thick layer over the garden and around trees and shrubs. It helps to eliminate weeds by depriving them of sunlight and keeps the soil from drying out. In addition, as the mulch decomposes, it adds vital nutrients to the soil.
One of the biggest advantages of using red cedar mulch is its ability to repel insects. Many other types of mulch actually attract insects such as roaches and ants. Just as a cedar closet repels moths, the aroma of the cedar mulch will keep many kinds of harmful insects at bay. It is high in plicatic acid, which is very effective in repelling ants and fleas, although its effects are lessened as the oils in the cedar break down. Fresh mulch needs to be applied periodically in order to keep on repelling these insects.
Soil temperature is also controlled by using red cedar mulch. When applied 5 or 6 inches (13 to 15 cm) thick, it helps to keep a consistent temperature, and also aids in keeping plants alive through severe weather. Their roots will stay cooler in hot summer weather when protected by this light colored mulch and will be sheltered from freezing temperatures during cold winters as well. This protection is also beneficial for plants such as clematis, which need full sun but require cool soil.
The use of red cedar mulch helps to keep plants stable in areas prone to soil erosion and heavy rainfall. While many other kinds of mulch are made of bark and wash away easily, cedar mulch is made in much smaller pieces of wood that form a thick, matted cover which stays in place. This helps plants stay upright on windy days and keeps roots from becoming exposed during hard rainstorms.
The disadvantages of using red cedar mulch are few; some gardeners, however, do not like the way it tends to mix in with the soil. This can be an issue when new plants are put into the garden, and digging causes the soil and cedar to combine and become messy. The mulch is also high in nitrogen and takes longer to break down and decompose than other mulches. Although this durability makes it attractive to many gardeners, those who prefer a mulch that rots more quickly often prefer to use compost, straw, or pine needles instead.
Red cedar mulch should be used with caution in areas accessible to dogs. Many dogs enjoy chewing and eating cedar; this can, however, cause diarrhea and stomach upset as well as splinters in the mouth and throat. Mulch chewing can be discouraged by using the shredded type of mulch, rather than the larger chunks.