Finding reaslistic greenery (usually specific plants) is always fun, and sources are always helpful. Looking for boxwood, I was suprised to see that Amazon sells in by the roll. A few months back I needed a very specific piece of laminate, which I also purchased off of Amazon because our local suppliers could not procur it. I remmeber propping in the 90's and how muh sites like ebay helped back then in the process of finding a needle in the haystack.
Also check out:
Silk Flowers Factory