per the Chicago Tribune:
The majority of countries that celebrate Mother’s Day do so on the second Sunday of May. On this day, it is common for Mothers to be lavished with presents and special attention from their families, friends and loved ones. There is a custom of wearing a carnation on Mother’s Day. A colored carnation means that the person’s Mother is living. A white carnation indicates that a person’s mom is dead.
President Woodrow Wilson signed a joint resolution in Congress on May 9, 1914, recommending that the federal government observe Mother’s day. The next year, the president was authorized to proclaim an annual holiday.
Typically, a family in the United States will devote Mother’s Day to activities in honor of Mom, whether playing games, going out to dinner, taking the weekend off. Flowers are popular, and it is also common to give Mother’s day cards and chocolate candies on her special day.