Flowers at a Catholic wedding
As with other decorations, flowers should not be placed in a way that interferes with the liturgy. They should not be placed on the altar, for instance. Ask your parish staff whether the church will already be decorated with flowers or other plants at the time of your wedding; you may want to incorporate these existing displays into your plans. Also, some parishes encourage couples who are being married on the same day to split the cost of flowers to be used at both ceremonies.
If you decorate the church with flowers, it is customary to leave the flowers behind for others in the parish to enjoy.