 Some mulches are better than others. I do not recommend plastic sheets or weed blocking fabrics because they provide nothing beneficial, cause heat buildup, and foul up the flow of oxygen in and carbon dioxide out of the soil. Best mulch is shredded native tree trimmings from your own property. Second best choice is shredded native cedar. Third in line, shredded hardwood bark. Pine needles work well but look a little out of place on your property where there's no pine trees growing.