Okay, I'm a total rookie at this, and I won't even pretend I know what I'm talking about. So please help me with this question. I have the opportunity to pick up the bid for the lawn maintenance of a shopping center. There is not a great deal of mowing or trimming, but there are a bunch of little islands filled with bushes and mulch. There are also several large gardens with mulch and bushes. The question is, "How do you determine how much mulch you need?" I understand how to find square footage, but, "How do you do so when the beds have shrubs and bushes in them?" And how do you determine the amount when asked to spread the mulch 1 1/2" to 2" thick?