One question that comes up this time of year a lot is what is the proper mulch to use for trees. Its easy to grasp the basic premise of mulch, but when people go to their local nursery they see many different kinds. How do you know which one to use? The short answer: wood chips.
The very best mulch to use for trees is something that is going to decompose gradually. Mulch made from wood chips fits the bill perfectly, since it rots slowly, and as an added bonus, this mulch is quite low in nutrients so will not encourage weed growth. Composted wood chips are the preferred material; these can be used as durable, low-maintenance mulch, which weathers to a silver-gray color.
The bad news is that most wood chip mulch is sold as fresh material, not in a composted or aged state. These chips also decompose slowly, but as they do decompose, microorganisms develop in the mulch and use nutrients from the soil that might otherwise be available for plant growth. Composted material will not support these microorganisms, which is why it is the preferred material. One solution to this dilemma is to buy un-composted wood chips ahead of time and compost them yourself. Put them in a...