In USDA zone 6, plant Lagerstroemia indica "Watermelon Red" for a shrub that produces red flowers. Its green leaves have a hint of bronze coloring in springtime, notes the Missouri Botanical garden, and the foliage turns yellowish-orange in autumn. Exfoliating bark, a trait of most crape myrtle varieties, is a feature on this shrub, which grows to 10 feet and blooms during the summer. Tonto, featuring fuchsia-colored flowers, grows smaller in zone 6 than it would in the Deep South. Maroon fall foliage and beige/cream-colored bark are aspects of this crape myrtle form.
Use Country Red in shrub borders or as a specimen plant in USDA zone 7, where it has few problems surviving the winter. Country Red is a cultivar dating back to the 1950s, known for red flowers from July into September. This form of crape myrtle grows between 4 and 10 feet tall. Houston is a small weeping-type of crape myrtle, between 12 and 24 inches high. Suited for rock gardens and foundations, Houston has red flowers, dense branches and dark green leaves.
Victor grows to 6 feet in USDA zone 8, producing dark red flowers all summer long. Victor has peeling red-brown bark and its foliage changes to hues of red-yellow during the fall. Victor serves as a hedge or screen as well as a specimen shrub. For bright red flowers, consider Baton Rouge. This variety of crape myrtle grows to 3 feet high and is appropriate as a container plant for use on your patio in zone 8.
USDA zone 10 is a bit too hot and sticky for most forms of crape myrtles with red flowers, but Gamad thrives there, generating cherry-red blooms. Gamad has a somewhat shorter blooming period, beginning in July and ending in August. In zone 9, the Whit II form of crape myrtle grows as large as 20 feet, making it a potential choice for planting along streets and driveways. Whit II has creamy-red blossoms and its foliage goes from reddish when it opens, to green and finally to orange and red by autumn.