One sure way to highlight the fall colors in your yard is to pair them with evergreens. Engelmann spruce (Picea engelmannii), Korean fire (Abies koreana 'Horstmann Silberlocke'), and dwarf blue spruce (Picea pungens 'Corbet'), for example, looks smashing against bold reds and oranges. And bright yellows practically sing next to a dark green background.
border in Thomas Rainer's garden, northern Virginia, May: Salvia, Nepeta, Nasella, ornamental Alliums. Kousa dogwood? Look at cool-season native grasses to see if any share the frosty chartreuse effect of the Nassella here.