“The use of the Advent wreath is a traditional practice which has found its place in the Church as well as the home. The blessing of an Advent wreath takes place on the First Sunday of Advent or on the evening before.
Customarily the Advent wreath is constructed of a circle of evergreen branches into which are inserted four candles. According to tradition, three candles are violet and the fourth is rose. The candles represent the four weeks of Advent.
When the blessing of the Advent wreath is celebrated in the home, it is appropriate that it be blessed by a parent or another member of the family.” [CCC 1509-1514]
Click here for a link to the USCCB and an exceprt from the "Catholic Household Blessings and Prayers" for blessing and praying with the Advent wreath.