Black mulch is made of ground up hardwood. The wood is ground up, watered, and then it is dyed to give it a rich black color so your flower beds are tastefully cared for. It is turned and mixed so it gets the durability and consistence that you would expect from Oak Lane Structures. Since it is made mostly from ground up hardwood it tends to break down more slowly than our Premium Bark Mulch. There are pros and cons to that. The benefit is that it will last longer and you might be able to cheat and make your mulch last 2 years instead of redoing it every year. Since it decomposes slower it doesn’t add nearly as much nutrients to the soil, and it will not hold as much moisture. So it all depends on what you are wanting to accomplish in your flower beds as to whether you want a bark mulch or hardwood mulch.