In Celtic myths the Green man was the God of fertility.

Later in the millennium, Early Christians banned green because it had been used in pagan ceremonies.

Nevertheless, as evidenced by this 15th Century wedding portrait, the color green was the best choice for the bride's gown because of its earliest symbolism.

Of note is the continued symbolism attached to the color in the latter part of this century. Anyone who chooses a green m & m (an American candy which contains an assortment of different colored chocolate sweets) is sending a somewhat similar message. Green has been reinterpreted by late 20th century American culture to signify a state of heightened sexuality in this specific situation.

Other bride colors:

White would be an inappropriate color for a wedding in China. It is the color of mourning. If a bride chooses a white wedding gown, her parents would probably not allow her to get married.

In India, even in Christian weddings, while most brides wear white, it is usually relieved by at least a touch of some other color. If a married woman wears unrelieved white in India, she is inviting widowhood and unhappiness.

Other cultural references for green:

Universal symbolism:
Nature, freshness

Contemporary symbolism:
Ecologically beneficial