White double begonias fill shade and part-sun beds with layered petals all summer long, reaching 1 to 2 feet tall depending on how much light they catch. They're not fragrant, but the ruffled flowers make up for it in sheer volume.

Plant them in groups for impact, or tuck them among hostas and ferns where they'll brighten a dim corner. Space them 6 to 12 inches apart and deadhead spent blooms to keep them coming through the heat.