桜伐る馬鹿梅伐らぬ馬鹿

Etymology
Literally “it is stupid to prune a cherry blossom tree and stupid not to prune a plum blossom tree.”

Proverb

 * 1) Cherry trees should not be pruned, but plum trees should. Although they may look similar upon first glance, each type of tree requires its own care procedures.

Usage notes

 * This proverb is almost always used with its literal meaning, in contexts about how to care for trees. It may be told to people who pull branches off cherry trees for social media picture purposes.