Bachelors' Buttons
Because they're blue?

Actually, blue for boys and pink for girls is a relatively recent phenomemon (as I understand) whereas this name no doubt has persisted for centuries. They certainly are a pretty color, and easy to grow, if only their lazy gardener would properly divide them.

This photograph was probably taken in 1999.

TIP:

Actually, I've since learned even more than division is the importance of cutting back—all the way to the ground—these plants once the leaves start getting nasty & brown. They come back with more beautiful flowers.