The earliest roots for the holiday may lie with the Greeks, and then Romans, who both had Spring festivals to honor the mother goddess. Often rituals such as these, evolve into our current holidays.
Slightly more recent roots of the holiday may lie in "Mothering Day," which has been celebrated in England for centuries.
The American beginnings of the Mother's Day holiday began with Julia Ward Howe. In 1872 she began a Mother's Day meeting in Boston, and continued the ritual each subsequent June 2nd. Several people in other cities began similar rituals.
A further development began at the turn of the 20th Century in the USA. Anna Jarvis was a young schoolteacher who lived in Grafton, W.Va. and Philadelphila, PA. Her mother died in 1905, and Anna wanted to honor her memory.
In 1907 Ms. Jarvis began a letter writing campaign to newspapers and politicians to make the 2nd Sunday in May, Mother's Day. Over the following years, official celebrations of Mother's Day were held in a number of towns and cities in May.
By 1914, Mother's Day finally received national recognition when President Woodrow Wilson signed a joint resolution recommending its observance. In 1915, Mother's Day was proclaimed a national holiday by President Wilson, to be celebrated on the second Sunday of each May.
Ms. Jarvis began the custom of wearing a single white carnation on Mother's Day. She wore it since it was her mother's favorite flower. Though the gesture was personal for her, carnations gradually took on a larger symbolism for all of Mothers Day. Nowadays, white carnations have become associated with mothers who are absent or have died... pink or red carnations for those still living.
The Flower industry and Greeting Card industry started to commercialize this holiday soon after. But Mother's Day has remained a nice balance of families celebrating their mothers with a meal, a gift, a card, or just heartfelt thanks...
***Sources for this information include an entry in World Book 2000 and an article by Leigh Eric Schmidt in the Journal of American History (Dec 1991) called "The Commercialization of the Calendar."