The Birthday Plan by Elisabeth Batt
This book is from the Junior Gateway Books series - a series of simple, easy-to-read stories in large print with a Christian message. Cherry and the twins have no present for their mother's birthday, but Cherry has a bright idea: their mother's name is Violet, so she should have a bunch of violets for every years of her age. So the next day the three of them take a picnic lunch, and go to the place where violets grow wild. But the birthday plan does not work out quite as Cherry had expected.