I just read a comment about buildings yielding flowers. I never had a building yielding flowers. Please..

3x3 buildings give you flowers when you purchase and upgrade them. There are a total of 6 upgrades, with the 6th one (Golden Facade) requiring purchase with gold bars. Once you've reached the 1st upgrade, they will generate coins at the rate of 1 coin every 40 minutes, until it reaches the max of 15 after 10 hours.