Hello. Apparently, you can duplicate flowers / plants by simply putting them in a flower pot that's placed on top of a slab. In order to make this easier for you to understand, I made a video here : http://www.youtube.com/watch?v=r1io7_nExe4

Hope you'll fix this soon ! Even though my parents won't allow me to get a normal minecraft account ( The one i am currently playing on is borrowed), I still want to help by improving the gameplay which is absolutely great at the moment.

Bye !

P.S.: You have to break the slab for the plant to duplicate, not the pot.