Peat moss is an excellent soil amendment for your acid-loving plants. There are approximately 12,000 species of moss, but it’s only the 380 species of sphagnum moss that create peat. Bogs and fens form where sphagnum grows because both living and dead moss absorb and store water. As it grows, it spreads onto drier areas and turns those into bogs as well.
Peat does not decay very easily in the bog conditions, due to the sphagnum cell structure and to slower-acting anaerobic conditions. Although it grows very slowly, it can accumulate to a depth of many meters. The live moss grows on top of the dead moss, and it is the dead moss that forms the peat we use in the garden.