Lagerstroemia Thunderstruck™ White Flash™ (Crape Myrtle)

Lagerstroemia Thunderstruck™ White Flash™ (Crape Myrtle) – White-Blush Flowers and Near-Black Foliage

Lagerstroemia Thunderstruck™ White Flash™, commonly called Thunderstruck White Flash crape myrtle or White Flash crepe myrtle, is a vigorous deciduous flowering tree prized for its vivid contrast between white-blush flowers and glossy foliage that matures to dark gray-purple or nearly black. Its upright habit, strong branching, and long summer display make it an excellent choice for sunny landscapes where dramatic foliage color is as important as bloom.

Sold under the Thunderstruck™ collection, this patented cultivar is Lagerstroemia × ‘JM6’ PP31556, identified in the patent as Lagerstroemia indica ‘JM6’. It commonly grows about 12 to 15 ft. tall and 8 to 12 ft. wide (3.6-4.5 m by 2.4-3.6 m), creating a substantial small tree without reaching the scale of Thunderstruck™ White Lightning™. Its intermediate dimensions suit lawns, broad borders, flowering screens, and specimen plantings.

The ruffled flowers are white to white-blush, sometimes appearing softly pink because of the dark flower stalks and surrounding buds. Blooming generally extends from summer through fall. The mature near-black canopy provides strong ornamental value even before the flowers open, and the foliage may develop orange tones in autumn before falling.

Quick Facts – Thunderstruck™ White Flash™ Crape Myrtle

Summary: Fast-growing dark-foliaged crape myrtle with white-blush flowers, glossy near-black leaves, and a vigorous upright habit.
Use: Excellent as a specimen tree, small lawn tree, flowering screen, large border accent, or informal hedge.
Highlight: White flower clusters appear to glow against the rich purple-black canopy, creating bold summer contrast.
Note: White Flash™ is smaller than White Lightning™ but still needs room for an 8-12 ft. canopy. Avoid severe annual pruning.

Botanical Name	Lagerstroemia × ‘JM6’ PP31556; identified in the patent as Lagerstroemia indica ‘JM6’
Trade Name	Thunderstruck™ White Flash™
Family	Lythraceae
Common Names	Thunderstruck White Flash crape myrtle, White Flash crepe myrtle, dark-leaved crape myrtle
Parentage	‘Ebony and Ivory’ × ‘Natchez’
Plant Type and Habit	Deciduous large shrub or small tree; upright to somewhat outward-spreading, freely branching, vigorous, sturdy, and commonly multi-stemmed
Hardiness (USDA)	Zones 6 to 9; stem injury may occur in colder Zone 6 sites
Size	Commonly 12-15 ft. tall and 8-12 ft. wide (3.6-4.5 m by 2.4-3.6 m)
Growth Rate	Fast; vigorous in warm, favorable conditions
Sun and Exposure	Full sun; at least 6 hours of direct sunlight, with 8 or more hours ideal
Soil	Average, moderately fertile, well-drained clay, loam, or sandy soil; slightly acidic to neutral conditions are ideal
Bloom Time	Summer through fall; late summer into autumn in patent trials
Flower Color	White to white-blush, sometimes appearing softly pink
Foliage Color	Developing leaves green; mature leaves dark gray-purple to nearly black, with a glossy landscape effect
Fall Color	May develop orange autumn tones
Disease Resistance	Observed resistance to powdery mildew and Cercospora leaf spot; good sun and airflow remain beneficial
Wildlife Value	Flowers may be visited by bees and other insects; best regarded as a supplemental floral resource
Deer Resistance	Not usually preferred by deer, but young growth may be browsed and trunks may be rubbed

Care – Quick

• Planting: Select a hot, sunny site with room for an 8-12 ft. canopy.
• Water: Water deeply and regularly during establishment; mature plants tolerate moderate drought.
• Feeding: Apply compost or a modest spring fertilizer only when growth or soil fertility is poor.
• Pruning: Prune selectively in late winter or early spring; never top the crown.
• Mulching: Maintain 2-3 in. of organic mulch without covering the trunk flare.
• Best use: Place where the pale blooms and near-black foliage can be viewed against a lighter background.

What Is Thunderstruck™ White Flash™ Crape Myrtle?

Description and Cultivar Identity

Thunderstruck™ White Flash™ is the commercial name for the patented cultivar ‘JM6’ PP31556. The patent identifies it as Lagerstroemia indica ‘JM6’, while current commercial material markets it as Lagerstroemia × ‘JM6’. It was developed through a breeding program focused on vigorous, freely branching crape myrtles with dark foliage and distinctive flower colors.

The cultivar originated from a controlled cross between dark-foliaged, white-flowered ‘Ebony and Ivory’ and the green-leaved, white-flowered cultivar ‘Natchez’. ‘JM6’ was selected for its greater vigor, larger mature size, dark gray-purple foliage, freely branching habit, and numerous white flowers.

Growth Habit and Mature Size

‘JM6’ develops an upright to somewhat outward-spreading framework with sturdy primary branches and numerous secondary and tertiary laterals. The dense branching creates a full canopy and supports a generous floral display. It is commonly grown as a multi-trunked tree, although young plants may be trained to fewer main stems.

A practical mature expectation is 12-15 ft. tall and 8-12 ft. wide. That places White Flash™ between dwarf crape myrtles and tall landscape trees such as Thunderstruck™ White Lightning™. Give it enough room from windows, narrow walks, roofs, and neighboring shrubs so its natural shape can be preserved.

Flowers and Bloom Season

The showy single flowers have six softly ruffled petals and are arranged in terminal panicles. The patent describes the petals as white, while commercial materials refer to white-blush flowers. Dark reddish buds, stems, and flower stalks can lend the clusters a pale pink cast when viewed from a distance.

Bloom is promoted from summer through fall, with patent observations recording late-summer and autumn flowering in Fort Worth, Texas. Timing varies with climate, heat, latitude, plant age, and establishment. Deadheading is unnecessary on an established tree and soon becomes impractical as the canopy develops.

Dark Foliage and Fall Color

Developing leaves begin green, then mature to dark gray-purple, often reading as nearly black in the landscape. The upper leaf surface is technically described as dull in the patent, while the overall canopy is marketed as glossy because of the color depth and the semi-glossy lower surfaces. Full sun promotes the darkest mature foliage.

Commercial materials report orange fall color, adding a warmer seasonal phase before leaf drop. Autumn intensity varies with climate and weather. After the leaves fall, the upright branching structure and smooth mature stems provide modest winter form.

Hardiness and Climate

Thunderstruck™ White Flash™ is generally recommended for USDA Zones 6 to 9. It performs best in regions with long, warm summers. Near the cold edge of Zone 6, winter injury may shorten stems, reduce mature size, or delay flowering. A sunny, protected site and a broad organic mulch layer can help protect the root zone.

Uses in the Landscape

• Specimen tree: Use as a high-contrast focal point in a lawn or broad sunny border.
• Small lawn tree: Add dark foliage and summer flowers without the height of White Lightning™.
• Flowering screen: Repeat several plants where a deciduous seasonal screen is appropriate.
• Informal hedge: Allow sufficient width and avoid maintaining it as a tightly clipped wall.
• Mixed border accent: Rise above pale grasses, silver foliage, and lower perennials.
• Foundation focal point: Use only where the mature canopy will remain clear of windows, paths, and vents.
• Patio or courtyard accent: Allow space for roots and canopy and account for flowers, leaves, seed capsules, or possible honeydew litter.

Wildlife and Pollinator Value

The flowers may be visited by bees and other insects, but crape myrtle is best considered a supplemental floral resource. Pair it with native perennials and grasses that provide nectar, pollen, seeds, and shelter over a broader season.

Deer and Browsing Animals

Crape myrtles are not usually the first woody plants selected by deer, but they are not completely deer-proof. Young shoots and low branches may be browsed, and trunks can be damaged by rubbing where deer pressure is high.

Drought and Heat Tolerance

Once established, White Flash™ tolerates heat and moderate drought. Newly planted trees require deep, regular watering while roots expand into the surrounding soil. Mature plants flower and retain foliage better when irrigated during prolonged dry periods, but poorly drained ground should be avoided.

Toxicity

Crape myrtle is not commonly regarded as toxic to people, cats, dogs, or horses. Nevertheless, ornamental plant material should not be intentionally eaten, and any concerning ingestion should be discussed with an appropriate medical or veterinary professional.

Invasiveness

Thunderstruck™ White Flash™ is not an aggressive spreading tree. Related Lagerstroemia indica material has naturalized in parts of the southeastern United States, however. Remove unwanted seedlings near sensitive natural areas and follow current regional guidance.

Growing Conditions for Thunderstruck™ White Flash™

Light

Full sun is strongly recommended. Provide at least six hours of direct sunlight daily; eight or more hours generally produce the darkest foliage, heaviest flowering, densest growth, and lowest fungal disease pressure. Shade can result in greener leaves, fewer flowers, and branches that lean toward available light.

Soil

The cultivar adapts to clay, loam, and sandy soil provided drainage is adequate. Slightly acidic to neutral conditions are ideal. Avoid low sites where water remains around the root crown after rain and do not create a narrow pocket of heavily amended soil.

Water

Water deeply after planting and whenever the developing root zone begins to dry. Deep irrigation encourages broad root development, while frequent shallow sprinkling does not. Once established, water during prolonged drought rather than keeping the soil continuously moist.

Feeding

Excess nitrogen can produce leafy shoots, delay flowering, and encourage aphid activity. Apply compost or a modest slow-release fertilizer in spring only when soil fertility or plant performance indicates a need. A soil test is preferable to routine heavy feeding.

Planting, Maintenance, and Propagation

Planting Tips

Plant in spring or fall with the root flare visible at or slightly above grade. Dig a hole wider than the root ball but no deeper, backfill with the existing soil, water thoroughly, and mulch over a broad area. Keep mulch several inches away from the trunks and allow for a mature spread of 8-12 ft.

Maintenance and Pruning

Crape myrtles flower on new wood, so necessary structural pruning is best completed in late winter or early spring. Remove dead, damaged, rubbing, crossing, or inward-growing branches and unwanted basal shoots. Thin selectively rather than stripping the interior canopy.

Never top White Flash™ or cut every branch back to large stubs. Severe annual pruning destroys the natural outline, creates clusters of weak shoots, and commits the owner to repeated corrective work. Select the right planting site rather than attempting to force a 12-15 ft. cultivar into a narrow bed.

Propagation

Thunderstruck™ White Flash™ is protected by U.S. Plant Patent PP31556. Unauthorized asexual propagation is prohibited while patent protection applies. Purchase correctly labeled plants from licensed nurseries rather than attempting to reproduce the cultivar from cuttings.

Problems and Pests

The patent records resistance to powdery mildew and Cercospora leaf spot, two important fungal diseases of crape myrtle. Resistance reduces the likelihood and severity of infection but does not guarantee completely symptom-free foliage under every combination of shade, crowding, humidity, and plant stress. Aphids, bark scale, spider mites, Japanese beetles, and other pests may still occur.

• Aphids: Colonies may feed on young growth and produce sticky honeydew.
• Sooty mold: Black fungal growth develops on honeydew from aphids or scale. Manage the sap-feeding insect rather than treating the coating alone.
• Crapemyrtle bark scale: White or gray felted insects may collect on trunks and branches, producing honeydew and sooty mold.
• Spider mites: Hot, dry conditions may encourage stippling, bronzing, and fine webbing on foliage.
• Cercospora leaf spot: The cultivar was observed to resist this disease. Open spacing, good airflow, and sanitation remain useful preventive practices.
• Powdery mildew: ‘JM6’ was observed to resist powdery mildew, although shade, crowding, and severe plant stress may still increase disease pressure.
• Japanese beetles: Adults may chew flowers and foliage where populations are high.
• Winter injury: Cold near the northern hardiness limit may damage stems and delay the following season’s bloom.

Design Ideas and Companion Plants with Thunderstruck™ White Flash™

These companions tolerate full sun, summer heat, and well-drained soil while providing enough contrast to display the dark canopy. Plant them beyond the immediate trunk zone and account for increasing shade beneath the tree as it matures.

• Blue-green vertical structure: Panicum virgatum ‘Northwind’ – upright blue-green blades create a lighter structural foil for the dark foliage.
• Silver-blue foreground: Salvia ‘Blue Spire’ (Russian Sage) – silver stems and blue flowers soften the base while tolerating heat and dry soil.
• Warm golden contrast: Rudbeckia fulgida var. sullivantii ‘Goldsturm’ – golden flowers create a vivid contrast with the white blooms and dark canopy.
• Airy pink movement: Muhlenbergia capillaris – pink fall plumes echo the flower blush and extend seasonal interest.
• Soft yellow foreground: Coreopsis verticillata ‘Moonbeam’ – pale yellow flowers brighten the planting without competing with the canopy.
• Native summer layer: Echinacea purpurea – coneflowers add stronger pollinator value and a sturdy upright foreground.

Frequently Asked Questions

References

Google Patents – United States Plant Patent PP31556, Lagerstroemia indica ‘JM6’: https://patents.google.com/patent/USPP31556P2/en

Justia Patents – United States Plant Patent PP31556, Lagerstroemia indica ‘JM6’: https://patents.justia.com/patent/PP31556

Garden Debut – Thunderstruck™ White Flash™ Crapemyrtle: https://www.gardendebut.com/plant/Thunderstruck-White-Flash-Crapemyrtle

SiteOne Portfolio – Thunderstruck™ White Flash™ Product Sheet: https://www.siteone.com/medias/sys_master/PimProductImages/assets/ProductAssets/US/Portfolio/specificationSheet/thunderstruck-white-flash-crape-myrtle-portfolio-product-sheet/thunderstruck-white-flash-crape-myrtle-portfolio-product-sheet.pdf

Clemson Cooperative Extension – Crape Myrtle Diseases and Insect Pests: https://hgic.clemson.edu/factsheet/crape-myrtle-diseases-insect-pests/

University of Florida IFAS Extension – Crapemyrtle Pruning: https://ask.ifas.ufl.edu/publication/EP399

Updated: July 2026 • Reviewed by Gardenia Editors