A wildflower "look" or "style" usually means: a large variety of textures, colors, and types of flowers used. Not more than 2 or 3 stems of any one flower, usually smaller headed flowers are used or flowers with multiple blooms. It also can mean a looser, unstructured design as well:
A wildflower bouquet in terms of weddings means using more field type flowers, or less formal flowers than what is traditionally used:
One mistake people often make is thinking "wildflower" means "less-expensive". Stems of "wildflower" cut flowers are either equal to, or more than, some of their traditional cousins
( i.e. roses, hydrangeas and lilies. ) These "wildflowers" are still commercially grown, exported cut flowers and still come with all the same costs to produce and ship them worldwide. Unless you are truly picking a flower from a field would you save any money. The field flower will not last as long as a commercially cut flower will last due to breeding.