One easy trick to help get plants established quickly, is to thoroughly loosen their roots before planting, shaking and teasing out as much of their potting soil as possible and mixing it with your natural soil. This helps plant roots get off to a strong start in just one kind of soil. It keeps soils from compacting and crusting, shades out weed seeds and enriches the soil as it is recycled into the soil by worms. Nearly anything will work as mulch, as long as it shades the soil but still lets air and water get to roots. They simply need freshening up once or twice a year, top-dressed with new mulch.
Mulches can strongly delineate a new flower bed or where grass has died out in the shade.
They give the appearance of good gardening, even when just covering up weeds right before a garden party. Some folks prefer the looks of pine straw, others like shredded cypress, but they all work about the same. Put down enough to barely cover the ground, then add that much more to account for settling. It may take 5-6 inches of pine straw, but only 3 inches of shredded bark. Multiply the width of the area by the length to get square footage, multiply that by the number of inches of mulch depth you want, divide by 12 to get cubic feet.