• Iris flowers bloom in a wide range of colors.Jupiterimages/Photos.com/Getty Images
  
  German iris (Iris germanica) is a perennial flower that is stunning planted with other summer-flowering perennials in a wide range of bright colors. German iris features six petals that are ranged into a trumpet shape and vary in color. The strap-like foliage on German iris grows in a fan-shape clump and is stiff. German iris grows best in full sun and well-drained, loose, humus-rich soil. Hardy, it also is deer resistant.
  
  

Stonecrop

• Stonecrop (Sedum makinoi 'Ogon') is an herbaceous perennial ground cover that looks stunning planted around the German iris. It grows ¼-foot tall and has a maximum spread of 1 foot. This tiny-leaved ground cover has a spreading nature and bright, bold foliage that complements the colors found in German iris plants. Stonecrop forms a dense mat and rounded leaves that reach ¼-inch wide. It bears star-like, yellow to green flowers that emerge in summer to add another layer of color and texture to the space. Plant stonecrop in the front of German iris plants to create a sea of bright color. Similar to German iris, stonecrop grows best in full sun to partial shade and well-draining, dry-to-medium soil. Hardy, it also is drought and heat tolerant once it has become established.
  
  

Balloon Flower

• Complement German iris plants with the balloon flower (Platycodon grandiflorus 'Astra Blue'). Like German iris, balloon flowers are summer-blooming perennials that create a burst of color to the garden. It has a clumping form and is "named because its flower buds puff up like balloons before bursting open into outward to upward facing, bell-shaped flowers with five pointed lobes," according to Missouri Botanical Garden. Balloon flowers grow to ½-foot tall and wide and feature blue flowers and oval, dentate leaves. It grows best in full sun to partial shade and well-drained soil. To encourage a second round of blooms, deadhead the spent flowers.
  
  

Dahlia

• Dahlia (Dahlia 'Bishop of Llandaff') is a summer-blooming perennial flower that has a clumping growth habit. It grows up to 3 feet tall and bears brilliant 4- to 6-inch-wide bright red petals that surround the deep purple and yellow centers. Plant a group of these stunning dahlias next to purple German irises for a commanding presence in the garden. The dark, blackish foliage on dahlia accentuate the colorful blooms to create a showy display. They grow best in full sun and rich, well-drained soil.