"Two Souls, but a Single Thought, Two Hearts, that Beat as One" John Keats

Ceremony decor traditionally involves pew and aisle decor, runners, altar arrangements, candleabras. Depending on the regulations from each church, you can use all or none of these options.  Outdoor ceremonies lend themselves more to floral arches, gazebo decor, draping fabrics, and more specific landscaping.  Tree branches and chair garnishes work great as well as rose petals.