I love this drawing. It has a number of messages. First i see a family. The man returns home and is unable to enter the house because his wife has the keys and she won't let him have it yet so she hides it. Her choice of place to hide the key seems strategic. There is a possibility that she longs for a sweet memory with her husband and her choice is a garden. Gardens are usually peaceful, serene, romantic atmosphere and the scent from the plants makes it all sweet. Since the man won't be able to find the spot where the key is hidden, he has to go through her and play the game by her rules.
Great painting