Pine bark mulch in gardens tends to last longer than most organic mulches, whether finely shredded or in nugget form. The natural red-dark brown color of pine bark mulch also lasts longer than other wood mulches, which tends to fade to gray after a year. However, pine bark mulch is very lightweight. And while this can make it easy to spread, it makes it inappropriate for slopes, as the bark can be easily moved by wind and rain. Pine bark nuggets are naturally buoyant and will float in circumstances with too much water. Any organic mulch benefits soil and plants by retaining moisture, protecting plants from extreme cold or heat and preventing the spread of soil borne diseases. This is true of pine bark mulch as well. Pine bark mulch is especially beneficial to acid-loving garden plants. It also adds aluminum to the soil, promoting green, leafy growth.