I (Maureen) asked the Blessed Mother if the scapulars needed to be blessed. She answered me saying, “The graces attendant to the scapular come through the images of the Two Hearts when They are venerated. The priest's blessing * does not change the graces promised, but brings with it the added grace of becoming a sacramental.”
* Note: In order for the scapular to be a sacramental, it must be blessed by the ordained ministry of the Catholic Church: bishops, priests, or deacons.