First : Happy Mothers Day to all to whom it may apply.

In US, the second Sunday in May is Mothers Day.
Do other countries have anything similar?

Now, when I was VERY young, I mean before WWII, there was a tradition that men wear a carnation to honor their mothers on Mothers Day : a white carnation if mother was dead, a pink carnation if mother was alive.
I don't remember its being reinstituted after WWII.

How did the carnation growers miss that one?

On equal time front : Fathers Day is in June