Check Bachmann's Plasticville line, buildings and other items for a fairly cheap price. The guys on the Classic Toy Trains forum might be able to help also. Bachmann at http://www.bachmanntrains.com/home-usa/catalog/
Good luck
Paul
You can use any scale trees, they will be just smaller types. Buy larger sized ones to look right. Grass and weeds using popular brands work. Use coarser groud foam etc. with common sizes. There is no "O" scale scenery that I know of just as there is no HO or N scale stuff. Used sizes that work in your chosen scale.
Dave
I am trying to find a good place to purchase scenry for an O Guage layout such as trees, telephone poles, etc. My trains are all HO scale so I have never looked for O scale at all. I am trying to find someplace to look that I can refer to a Mom down the street that has no idea where to even start. I told her if she could find it I would help her build the train layout for her two sons.
Thanks in advance
George