The best kind??? I would say anything that is spread atleast 3-4 inches deep. Logically, darker colored mulches would work a bit better, but there is no evidence of real difference. As far as pre-emergents are concerned, yes, they make a huge difference. Tupersan is one to be considered. We use a product known as Snapshot that is sold commercially, but you can get the same thing in a lesser concentrate in a store bought product called Preen.
hmm, i've used preen and had no luck. i guess it only last 30 days or so.
this year i tried snapshot and treflan and the scotts version (cant remeber the name), but i didnt really notice a difference. i thin k the mulch i used was junk
I used a 4" layer of pecan shells in my planters at home when I first built them. They lasted about 8 years before decomposing and rarely had a weed. Went back to get some more and was told that they weren't being sold to the general public any longer. They were being shipped to a bio-mass place for generation of electricity. Too bad.