Last year I had a sprinkler system installed. I also asked them to spread organic mulch on all beds. Since I was not the one ordering the mulch from a compost farm I had no way to be sure they delivered exactly what I ordered but I trusted the company. Big mistake. Organic mulch looks pretty much like any other mulch. On top of that, I believe I did not get composted mulch but instead I paid for organic composted mulch but got cheap dyed shredded bark, which has leeched all the nitrogen out of the soil and caused everything except the hardiest shrubs and trees to die. My vegetable garden has not recovered yet, even though I scraped the offending "mulch" off of the bed, turned the soil, and added my own compost. So sad!
For more information on bad mulch read this blog post by one of the best gardening bloggers, Brenda Beust Smith, "The Lazy Gardener."