The question of whether purple trees exist finds a direct answer in botany, though the vibrant hue is rarely uniform across the entire plant all year. This striking coloration is typically concentrated in either the flowers or the foliage. To be considered “purple,” a tree must display a color spectrum ranging from lavender to deep burgundy or violet in a prominent part of its structure. These trees offer a spectacular visual contrast in the landscape, whether the color is a fleeting seasonal display or a continuous feature throughout the growing season.
Trees with Purple Flowers
The purple tree most often imagined is one that bursts into a canopy of lavender blossoms, exemplified by the Jacaranda (Jacaranda mimosifolia). This tropical species is famous for its dense clusters of trumpet-shaped, lavender-blue flowers that appear in late spring or early summer. The bloom is seasonal, often lasting for four to six weeks, temporarily transforming the entire crown of the tree into a purple spectacle.
Another prominent example is the Crape Myrtle (Lagerstroemia), particularly cultivars like ‘Twilight’ or ‘Catawba,’ which feature rich, deep purple flowers. Unlike the Jacaranda, these trees offer an exceptionally long blooming period, often from mid-summer until the first frost. The petals have a crinkled, crepe-like texture, adding visual interest to the vibrant purple shade.
Trees with Purple Foliage
For trees that maintain a purple color for the majority of the year, the focus shifts from flowers to the leaves, which possess genetic traits causing them to produce purple pigments persistently during the growing season. The European Purple Beech (Fagus sylvatica ‘Purpurea’) is a large, majestic example whose leaves emerge reddish-purple in the spring and deepen to a dark, glossy burgundy throughout the summer. This continuous coloration makes it one of the most prominent purple trees in temperate climates.
Smaller ornamental trees, such as the Purple Leaf Plum (Prunus cerasifera ‘Pissardii’), showcase a dark, reddish-purple leaf color from the moment the leaves unfurl until they drop in the autumn. The Japanese Maple (Acer palmatum), specifically varieties like ‘Bloodgood,’ also maintains deep wine-red to purple foliage throughout the summer months. The purple hue in these trees is a stable characteristic of the cultivar, not a transient response like the color change seen in autumn leaves. The intensity of this coloration often depends on sunlight exposure, with leaves in full sun displaying the deepest shades.
The Science Behind the Color
The purple, red, and blue colors in trees are primarily due to a group of water-soluble pigments called anthocyanins. These compounds are flavonoids synthesized by the plant and stored in the cell vacuoles of the flowers and leaves. Anthocyanins appear purple when they are present in high enough concentrations to mask the green color of chlorophyll, the pigment responsible for photosynthesis. The specific shade of purple is influenced by the acidity (pH) of the cell sap, with more acidic conditions favoring redder hues.
The presence of anthocyanins can be a stable genetic trait in purple-leaf cultivars, or the production can be a temporary response to environmental factors. For many trees, the synthesis of anthocyanins is triggered by stressors like intense sunlight, cold temperatures, or nutrient deficiencies, acting as a form of photoprotection.