AUGUST CAN BE HARD on the garden. Which only serves to spotlight the beauty of crape myrtle (Lagerstroemia sp.), a flowering tree that shows up with a dazzling display in the dog days of summer. 

Crape myrtles love full sun and heat — lots of heat. Reflected heat from neighboring buildings and surrounding asphalt, a difficult growing condition for most plants, provides an ideal environment to bring on the blooms. Indeed, a mature stand of several crape myrtles in the parking lot at the Center for Urban Horticulture is a sight to behold in late summer. 

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But here’s the catch. 

Flowering is determined by when the plant has accumulated a certain number of hours of temperatures above 85° F. So, a variety that begins blooming in June in southern states might not begin flowering until late summer here in the Pacific Northwest. The good news is, with proper placement and good growing conditions, once a crape myrtle begins to flower, the tree will continue to produce flushes of subsequent bloom for six to eight weeks. 

Bloom time varies by cultivar, but generally commences in August or September, when panicles of deep red, hot pink, lavender or white blooms appear on multitrunked trees that vary from upright and vase-shaped to a low profile with a spreading canopy. Excellent candidates for small gardens or tucked into the back of a sunny perennial border, crape myrtles benefit from regular water beginning in late spring, when the trees are leafing out for the best flowering performance. Dry conditions will delay flowering. 

Blooms are but one of crape myrtle’s charms. The trees are worth growing for their graceful form, and as summer fades, the glossy green foliage turns fiery shades of orange, gold and red in one of our region’s most vivid displays of seasonal color. Attractive mottled bark on muscular bare branches extends the show into winter. 

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Xera Plants, a Portland-based nursery that specializes in climate-adapted plants for Northwest gardens, has trialed Lagerstroemia for decades. Co-owner Greg Shepherd advises customers to select early-flowering varieties of crape myrtle for the most reliable blooms in our sometimes-heat-challenged Seattle gardens. Listed by size, his recommendations include: 

● Cheyenne (L. × fauriei ‘Cheyenne’) grows to 11 feet tall with a vaselike form and reliable flowering habit. Vivid strawberry red blooms are described in the Xera catalog as “wildly showy for weeks into early autumn.” Fall color is excellent, and the bark is dappled with pink and brown. 

● Hopi (L. × fauriei ‘Hopi’) produces billowing pink blooms on small trees to 12 feet tall and nearly as wide, with a full rounded canopy. According to the Xera catalog, ‘Hopi’ is one of the “very finest” summer-blooming trees and, relative to other varieties, requires the least amount of additional water. 

● Osage (L. × fauriei ‘Osage’), deemed “exceptional” by the Xera plant folks, has luscious pink blooms from August through October, brilliant red foliage in fall and exquisite mottled bark. ‘Osage’ grows to 16 feet high by 10 feet wide with a semi-pendulous form. 

● Natchez (L. × fauriei ‘Natchez’) grows to around 20 feet tall, with draping panicles of pure white blooms. Glossy dark green leaves turn vibrant orange-red in autumn before they fall, revealing exfoliating cinnamon bark. 

● Wichita (L. × fauriei ‘Wichita’) is fast-growing to 25 feet with a vase-shaped habit and a spreading crown. Lavender blooms show up in late July through September, followed by red, orange and purple fall leaf color. 

For more information about crape myrtle, including cultivating tips for growing this showy tree in Pacific Northwest gardens, visit the Xera Plants website (xeraplants.com).