The genus \(Lagerstroemia\), commonly known as the Crepe Myrtle, is a highly popular ornamental shrub and tree valued for its ability to produce vibrant, long-lasting color throughout the hot summer months. Prized across temperate and subtropical regions, its prolific flowering displays often persist for several months from mid-summer into autumn. The broad spectrum of colors available through decades of horticultural breeding is the main factor driving its widespread adoption in landscapes.
The Primary Crepe Myrtle Flower Color Families
Crepe Myrtle flowers are primarily categorized into four distinct color families, offering a spectrum of hues from the palest shades to the deepest saturation. The white family includes cultivars that display pure, crisp blooms, such as ‘Natchez’ and ‘Acoma’. These selections provide a classic, cooling contrast to the vibrant colors of summer landscapes and maintain elegance through high heat.
The pink family is one of the most extensive, ranging from soft, delicate shell pinks, seen in varieties like ‘Comanche’, to brighter, more intense rose and magenta shades. Cultivars like ‘Tuscarora’ are known for their deep coral or dark pink tones, representing the middle ground between light pinks and true reds. This range allows for subtle or dramatic effects in the garden.
Red flowers are highly sought after, with breeders focusing on achieving true, non-fading scarlet and crimson hues, such as those found in ‘Dynamite’ or ‘Red Rocket’. These deep red colors are created by high concentrations of specific pigments. They are particularly sensitive to environmental conditions, sometimes appearing pinker if light is insufficient. Cultivars like ‘Centennial Spirit’ present a vivid, dark red display with a slightly darker, richer tone.
The purple family includes colors spanning from light lavender to deep violet and plum, offering a sophisticated alternative to brighter pinks and reds. Cultivars like ‘Zuni’ and ‘Muskogee’ are known for their clear lavender flowers. ‘Twilight’ or ‘Purely Purple’ offer a very dark, almost black-purple saturation, providing a dramatic, rich color that often complements the darker green foliage.
Beyond Blooms: Color Variations and Seasonal Interest
The color appeal of the Crepe Myrtle extends beyond single-color panicles, incorporating subtle nuances within the flower and providing year-round chromatic interest. Some varieties exhibit bicolored flowers, where petals feature a distinct mixture of two shades, such as pink blended with white or a deeper color with a contrasting edge. This two-toned effect, sometimes described as a picotee edge, is often more pronounced when the weather is cooler during blooming. Cultivars like ‘Bicolor’ demonstrate this pattern with petals that are a mix of reddish-pink and white.
As the flowering season concludes, the plant offers a secondary color display through its autumn foliage, transitioning from summer green to vibrant seasonal colors. Leaves on various cultivars can display bright yellows, fiery oranges, or rich reddish-purple tones before dropping for the winter. This fall transformation, seen in varieties like ‘Natchez’ (which turns yellow and orange-red), adds significant value to the plant’s seasonal appeal.
During the winter months, the exfoliating bark provides a third layer of color interest, a distinctive feature of mature Crepe Myrtles. The outer bark peels away in thin strips, revealing the smooth, mottled under-bark in shades of tan, gray, or cinnamon brown. This striking, multi-hued trunk and branch structure ensures the plant remains an attractive focal point even without leaves or flowers.
Environmental Factors Affecting Color Expression
The final intensity and precise shade of a Crepe Myrtle flower can be influenced by external growing conditions, even within a genetically stable cultivar. Flower color is largely determined by the pigment called anthocyanin, which requires sufficient light for its full development. Cultivars bred for deep reds and purples are particularly dependent on full sun exposure; insufficient light can result in duller, paler, or pinker blooms than expected.
Cloudy or overcast weather during bud development can prevent anthocyanin from fully developing, sometimes causing deep-colored flowers to open with a washed-out or partially white appearance. While soil pH dramatically affects the color of some plants like hydrangeas, its effect on Crepe Myrtles is less pronounced. However, an alkaline soil can sometimes cause colors to look faded. Crepe Myrtles prefer a slightly acidic soil with a pH between 5.0 and 6.5.
Temperature also plays a role in color saturation, as extreme heat can cause the deepest red and purple shades to temporarily lighten or “bleach.” Conversely, cooler temperatures can intensify the depth of color, making the picotee edges on some varieties more apparent. These environmental factors explain why the color of a newly purchased plant may vary once established in a different location.