The crane is a magnificent bird which finds a lifelong mate and is very loyal to its partner. Folding a crane takes time, patience and understanding. These same qualities are essential for a lasting marriage.
The ancient practice of a man or woman folding 1,000 cranes for their wedding is called "sembazuru". The tradition itself is called "tsuru wa sennen". It is said that the time and energy put into the project symbolizes the patience and faith necessary to support a happy marriage.
Origami crane colors at a Wedding may have meaning to the couple. Sometimes the cranes are strung on garlands to decorate the venue, while some are used as place markers or table favors. Here is a recent real wedding from the Overlook in which the groom folded 3000 cranes for use in their table décor (look closely as the cranes are in the vases, on the willows and placed around the table). I guess they will be blessed with a happy marriage x 3!