Why can't I move forward in the game after I have redecorated?

You must add the necessary flowers to your island to advance to the next level. Look at how many more flowers are required in the top right corner, next to the flower symbol. Flowers can be obtained by buying decoration, renovating landmarks, or deliver from Jack's Delivery Service. If buying decoration, the construction must be complete and you must remove the red ribbon, before you will receive the flowers.

It sucks the way they have it set up and really limits your ability to decorate your island the way you would like. Once you get higher up and run out of island space you can't have roads or anything else just high level buildings stacked on top of each other. There is no way around this. You have to keep playing the same scenes again until you have money to buy expensive buildings that have high flower levels. Then you have to wait days unless you gem until construction is done and remove the red ribbon to receive your long awaited flowers. I am sure the developers have received many complaints regarding this system but they haven't changed it in the years I have been playing. Until they get it there is no other way to proceed. It's probably so you will buy diamonds and can buy instant decorations.