Yes, the Lowe's in College Station sells shredded cedar mulch (which is what you really want) a couple of nice brands of compost, one manure and one mushroom compost, and a full selection of organic products like seaweed, molasses, fertilizer, foliar feed products, etc. Contrary to popular belief, there are plenty of people in College Station who are interested in and use organic means.
As far as trees, you can't go wrong with a native oak but there are plenty of trees that would work well where you are. Same with perennials. Howard's book Plants for Texas is a really easy reference to use for what you want. Go to the library and look for it.
Good luck with your project!! I hope I was helpful to you.
Kathe