‘;UF15-6-28’; is a new Coleus plant with novel characteristics that include excellent heat tolerance, distinct, lance-shaped leaves that display a unique and consistent crimson and chartreuse coloration pattern, and a vigorous, compact mounded growth habit with excellent lateral branching. ‘;UF15-6-28’; exhibits superior foliage color stability when grown under all conditions, including both sun and shade conditions. Further, ‘;UF15-6-28’; exhibits long-season performance until late fall.