Butterfly Bushes

• The butterfly bush (Buddleja davidii) is a staple of cottage and butterfly gardens, typically in bloom during the summer when many other shrubs no longer are. Royal Red is a cultivar considered by the University of Connecticut Plant Database as a superior form, with panicles (clusters) of magenta flowers as long as 20 inches. Miss Ruby, with its pink-red flowers, grows between U.S. Department of Agriculture plant hardiness zones 5 through 9, as does Royal Red. Both these butterfly bushes can reach 5 feet tall in full sun, dying to the ground in the colder zones during winter before coming back strong in spring.
  
  

Crape Myrtles

• The crape myrtles are not cold-hardy shrubs, but plenty of options that produce red flowers are available for warmer zones such as zones 6 through 9. Victor is a rounded cultivar growing to 6 feet that features deep red flowers from July through September. Victor excels in full sun in areas with good drainage. Watermelon red grows as high as 10 feet, making it possible to create informal hedges and privacy screens with this crape myrtle. The red flowers bloom from June into September on Watermelon Red, and its foliage changes from dark green to pale yellow and orange shades.
  
  

Weigelas

• Old-fashioned weigela (Weigela florida) has a two-week period during May or early June during which it blooms heavily, before then flowering off and on during the summer. This shrub performs best in full sun, is easy to transplant and grows between 6 and 9 feet tall and up to 12 feet wide. It is suitable in zones as chilly as zone 5. Tango is much smaller, between 24 and 30 inches, with cold tolerance to USDA zone 4. It will produce more flowers when you put it in full sun; those in the shade generate fewer flowers. Tango works well in group plantings or as a foundation plant.
  
  

Shrub Roses

• Firefighter is a hybrid tea rose for full sun in zones 7 through 11. This cultivar takes its name to honor the firefighters lost in the September 11, 2001, terrorist attacks, says the Washington State University Clark County Extension. Firefighter grows 4 feet high, and the bush blooms from May through October, generating red roses with as many as 45 petals. Red Cascade is a climbing miniature rose that serves as ground cover or on patios, maturing to just 12 inches. Red Cascade works well as a container plant, blooming from May until first frost.