The Cherry Garden is the name of a a Set that was released in the 2017 Spring Event. It contains 5 buildings in it. When these 5 touch each other/ are adjacent to each other they receive certain bonuses. Details can be found on their pages.
Placing a Cherry Garden building next to a copy of itself won't result in the bonuses. They have to be placed separately.
The five buildings are:
This is the ideal configuration in which they have to be placed: