While this tip from Ruth Wyeth Spears and the 1920s describes a plaited (pleated) trimming for a "young girl's frock", I think this excellent tip would also apply to a frock for any age!
In her usual marvelous style, Ruth guides her home sewists with clear illustrations and precise steps. And note her tip for the novel feature of flipping the hem to the outside and trimming it in place with the plaiting (pleating). So clever and so simple - I love it!
Ruth recommends a crisp fabric as most effective, and says the sketch is of "changeable pink taffeta". I can picture this frock in pink taffeta - can you?