Mothers Day (also known as Mothering Sunday because it always falls on a Sunday) is celebrated on Sunday 3 April in the UK.
In the USA they wait a month and so the date for Mother's Day is May 9th.
Ancient Greeks and Romans had springtime festivals in honour of 'mother' gods. The goddess Brigid was worshiped by Celtic tribes with a spring Mother's Day. Therefore, buying gifts and pampering mothers on mothers day is a long held tradition. Don't just get her a card and chocolates. It isn't only about gifts. It is about showing how much you value your mum.