The answer to 'why is my mulch' is that there can be several common causes for mulch issues. Mulch can become matted, discolored, or break down over time due to factors like weather, decomposition, or improper application. Symptoms may include a foul odor, mold growth, or the mulch losing its aesthetic appeal.
Some solutions include refreshing the mulch by raking it to loosen and aerate it, adding a new layer of fresh mulch, or replacing the mulch entirely if it has significantly decomposed. For more serious issues like weed growth or pest infestations, it's best to consult a professional landscaper who can properly diagnose and treat the problem.