The answer to 'mulching yellowing' is that there are several common causes, including excessive mulch, improper mulch application, and nutrient deficiencies in the soil. Symptoms include yellowing, wilting, and stunted growth in your plants. To address this issue, you'll need to adjust your mulching practices and potentially amend the soil.
First, check the depth of your mulch. Mulch should be no more than 2-4 inches deep around plants. Excess mulch can smother plant roots and prevent oxygen and water from reaching them, leading to yellowing leaves. Spread out or remove any excess mulch. Next, ensure you're using the right type of mulch. Organic mulches like wood chips or shredded bark are best, as they break down over time and enrich the soil. Inorganic mulches like rocks or gravel don't provide the same benefits.