Mehndi is associated to lot of things, such its dark red color is consider a sign of good luck married couple. It is common that names of bride and groom are to be hidden in the mehndi design and the wedding night cant commence until the groom has found the names.some common examples are Lotus Flower, Peacock, an Elephant with raised trunk which is consider a sign of good luck etc.
The night of Henna is celebrated by most groups in Middle East countries and Asia-pacific region where henna is grown naturally with hot and dry weather conditions.