My fiance is German, and thankfully this land offers several beautiful traditions.
The first, and probably my favorite so far, is the tradition of pre-drawing a heart on an old sheet. At the ceremony, the groom cuts one side and the bride the other, meeting in the middle. The groom then carries the bride through the center to symbolize their new marraige.
Next is log splitting. This kind of quirky tradition symbolizes the need to work together to get through difficult times and emphasizes teamwork.
This is an Irish tradition and is basically fancy knot twisting. However, the tradition symbolizes unity and the intertwined nature of the husband and wife relationship.