"衣裙上的荷边装饰" can be translated into English as "ruffled trim on the dress" or "lace/frill edging on the skirt/dress" (depending on the specific type of "荷边," which could refer to ruffles, lace, frills, or other decorative edges).
Ruffled trim emphasizes the gathered or pleated fabric edge.
Lace/frill edging specifies the material (lace) or style (frills) of the decorative border.
For a more general term, "decorative ruffled/frilled edges on the dress" also works well.