Organic Black Mulch
Organic black mulch is often used to identify rich compost or a combination of deeply colored compost and shredded bark or humus and other organic materials. Composted materials derive their rich dark brownish black color from the heating, oxidation and microbial action found in a compost pile.
Recycled Rubber Black Mulch
Recycled rubber mulch is made of old tires stripped of their steel wires and shredded into varying grades or sizes of mulch pieces. The tire rubber is already black and therefore does not need to be dyed. Rubber mulch is used in commercial gardening and even more widely as a playground floor material in lieu of sand or bark.
Dyed Black Mulch
Shredded bark, wood ships, wood shavings, cocoa hulls and an number of other organic materials are dyed black for use as a decorative mulch choice beyond the natural hue of the wood or fibers. The organic materials are either sprayed with an indelible dye or tumbled with wet or powder dyes in drums to coat them.