Autumn leaves

Okay guys... just say my latest play requires autumn leaves for the opening scene act 2...I can of course go around merrily collecting said leaves, however, given the shows probably not going on until the summer, how can I preserve them so they don't crumble through a 2 week season? Note: Said leaves make a brief appearance, all of 3 minutes but they are vital to the scene...alternatively, how can I make realistic impressions? Note: at the close of the scene the leaves need to be collected for the following night, unless of course I collect enough to use fresh dead ones each night..????? Ideas anyone. cheers Johnny Grim Just a lad productions