green guide

A fresh layer of wood mulch gives any landscape a new and attractive look, but as time proceeds and seasons change, vibrant colors inevitably fade. Luckily, mulch is typically spread to a depth of three to four inches, and can easily be rejuvenated.

This technique differs pending on the type of wood mulch in your landscape. More dense mulches like Cascade Shredded Cedar (Gorilla Hair), Redwood, Shredded Fir, and Shredded Bark typically have the best results, and will last about five years before it need replenishing. (keep in mind that higher wind areas will need more maintenance than lower wind areas)
You may not have the greatest results with less dense mulches, which may need replenishing more often.
Our company uses a special machine with spinning metal tines for this process (image 1), or a hard rake which works just as well. Pull through the top layer of wood mulch to loosen the material (image 2). The wood below the top layer should have been protected from the elements, and retained it's color. Shift the lower levels of wood mulch to the top, and mix it with the faded wood (Image 3). 

This process may take a little time, though well worth the effort. Repeat the process until you are no longer satisfied with the results. Then it's time to add a brand new layer.