The answer to 'mulching yellowing' is that mulch can sometimes cause grass or plants to yellow if it is applied too thickly or not properly maintained. Mulch that is too deep or not regularly replenished can deprive the soil of oxygen and prevent water from reaching the roots, leading to yellowing and stunted growth.
To prevent mulch-related yellowing, apply a 2-4 inch layer of organic mulch like wood chips or shredded bark around plants and trees, keeping it a few inches away from the stems or trunks. Regularly check the mulch depth and replenish as needed to maintain the optimal thickness. Also ensure the mulch is not compacted or matted down, which can restrict airflow and water absorption.