Crapemyrtle (Lagerstroemia) Shrubs and Trees
Hardiness, Site Selection, Cultivation, Diseases and Landscape Use
May 30, 2009
Cultivars of Lagerstroemia indica and its hybrids with L. fauriei are hardy to USDA Hardiness Zones 7 to 9. L. fauriei and its cultivars are reliably hardy as far north as USDA Hardiness Zone 6.
Landscapes throughout the crapemyrtle growing range exhibit overused cultivars planted without attention to site or design objectives. Newer crapemyrtle cultivars receive little or no consideration. The best way to ensure that crapemyrtles remain low maintenance and fit the design is to use cultivars that best suit landscape needs. (Photo #1)
Crapemyrtle (Lagerstroemia) Cultivation and Site Selection
Crapemyrtles are relatively low-maintenance plants that thrive in full sun and moist, well-drained soil. They produce 6–8" long and 3–5" wide flower clusters from July through September on new or current year's growth. (Photo #2) Summer blossoms vary from white, pink, purple to deep red on different cultivars.
Crapemyrtles do not require heavy pruning for good blossoms. They actually produce flowers without any pruning, but profuse and larger blossoms emerge after light late winter or early spring pruning that stimulates new spring growth. Encourage a second summer bloom by clipping faded flowers.
Crapemyrtle (Lagerstroemia) Diseases
Powdery mildew and Cercospora leaf spot are two diseases that damage crapemyrtles. Neither jeopardizes health of established crapemyrtles, but may diminish their landscape beauty. "Putting Up Resistance: Selected Crapemyrtle Cultivars Resist Powdery Mildew and Leaf Spot," Highlights of Agricultural Research, volume 45, #2, summer 1998, reports on an Alabama Agricultural Experiment Station (AAES) trial conducted by Professor Austin Hagan, Plant Pathology, Professor Gary Keever, Horticulture, Professor Charles Gilliam, Horticulture, and Associate Professor David Williams, Horticulture.
The report identified crapemyrtle cultivars that are highly resistant to both powdery mildew and Cercospora leaf spot. Cultivars of L. indica showed more susceptibility to powdery mildew than L. indica x fauriei hybrids and L. fauriei 'Fantasy'. A few cultivars demonstrated good resistance to Cercospora leaf spot. Symptoms on the leaf spot-resistant cultivars 'Tonto,' 'Tuskegee,' 'Tuscarora' and L. fauriei 'Fantasy,' were light, usually inconspicuous leaf spotting around the plant's base.
Crapemyrtle (Lagerstroemia) Landscape Use Selection
During the last part of the 20th century, the U.S. National Arboretum, land-grant universities and individuals selected and distributed superior cultivars of common crapemyrtle (Lagerstroemia indica,) Japanese crapemyrtle (L. fauriei) and L. indica x fauriei hybrids. Extraordinary flowers, autumn leaf color (Photo #3) and year-round exfoliating bark along with varying sizes and forms create crapemyrtles that are four-season plants.
Diverse sizes and forms of recently introduced crapemyrtles make them very good choices for specimen plantings (Photo #4), in group or massed beds underplanted with evergreen groundcovers, or as hedges or screens. Sizes and forms of crapemyrtle selections and hybrids include:
1. Shrubs: True Dwarf – 2 to 5' and Semi-Dwarf – 5 to 12'
- Semi–pendulous,
- Dense,
- Spreading, or
- Arching.
2. Trees (either single or multiple stems): Small to Intermediate – 13 to 20' and Large – 21 to 33'
- Upright,
- Rounded,
- Broad-spreading,
- Vase-shaped, or
- Arching.
Crapemyrtle (Lagerstroemia) Locations for Comparison and Study
- The United States National Arboretum (U. S. N. A.) is significant for influencing crapemyrtles' functions in southern garden landscapes. The Gotelli Collection of Dwarf and Slow Growing Conifers shows crapemyrtles, Japanese maples, ornamental grasses, and other material with the conifers to dramatize seasonal changes. Administration Building gardens highlight plant introductions developed by Arboretum scientists over decades of plant breeding and research.
An Arboretum poster, on sale to the public, displays 29 images and descriptions of crapemyrtle varieties and cultivars introduced by the Arboretum. In December 1999, Arboretum horticulturist Ruth L. Dix compiled a relatively comprehensive list of Lagerstroemia cultivars and names. Originally posted to the Arboretum website January 6, 2005, a revised list was posted May 25, 2005.
- The JC Raulston Arboretum of North Carolina State University, Raleigh exhibits over two dozen crapemyrtle (Lagerstroemia) species, selections and hybrids in formal and informal garden settings (Photo #5). The Arboretum website contains a searchable database of current plantings which links to Arboretum collection photographs.
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