The boutonniere is traditionally worn in the buttonhole on the left lapel of a man's tuxedo or suit jacket. The word boutonniere is derived from the French word for buttonhole, specifically referring to the buttonhole on a man's lapel.

The grooms boutonniere should be distinct from those of his groomsmen. Often one of the flowers used in the bride's bouquet is repeated in the boutonniere.

The other men in the wedding party shouldn't match the grooms exactly but should be similar either in color or flower variety.  If the groom wears a red rose, then the other guys could wear a white rose for instance. The groomsmens should complement the bridesmaids bouquets however.

Boutonnieres for the fathers, stepfathers, grandfathers, readers or any other male who will receive one do not have to be the same as the groom and groomsmen. It is appropriate to match them to the corsages of their wives.