Plant a Tree or Pot a Plant
If you're getting married outside, consider planting a sapling—it represents growth, something you and your new spouse will do (a lot of!) together. During the ceremony, the bride and groom should place soil from two separate containers on top of the planting, representing two individuals coming together as one.
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This works for outdoor ceremonies, of course, but it allows couples throwing an indoor reception get in on the planting fun. Take a cue from this bride and groom, who potted and watered a plant together during their ceremony to represent the joining of their families.