Trees often display red hues, adding visual interest to landscapes. This coloration can appear in leaves, bark, flowers, and fruits. The reasons for these red displays range from seasonal biological processes to inherent genetic traits. Understanding these variations helps appreciate the dynamic beauty trees offer.
The Science Behind Red Foliage
The red colors in tree foliage, particularly during autumn, result from biochemical changes within the leaves. Throughout the growing season, leaves appear green due to chlorophyll, the primary pigment responsible for photosynthesis. As days shorten and temperatures cool in autumn, trees prepare for dormancy, and chlorophyll production slows and eventually stops.
With the breakdown of chlorophyll, other pigments already present in the leaves become visible. Carotenoids, which produce yellow and orange colors, are unmasked, giving trees like birch and aspen their golden tones. Simultaneously, many trees produce anthocyanins, responsible for rich reds, purples, and crimson. These water-soluble pigments are synthesized in the leaf’s cell sap, often in response to bright light and accumulated sugars.
Anthocyanins are thought to play a protective role, acting like a natural sunscreen by absorbing excess light that could damage the leaf’s cells as chlorophyll degrades. This protection may allow the tree to reabsorb valuable nutrients from the leaves before they fall. Environmental factors influence fall color intensity; warm, sunny days followed by cool, non-freezing nights, and adequate summer rainfall, generally lead to vibrant displays. Common trees known for their red fall foliage include Sugar Maple, Red Maple, various Oak species, and Sumac.
Trees with Year-Round Red Leaves
Beyond seasonal changes, some tree species and cultivated varieties maintain red or reddish leaves throughout their active growing season. This persistent coloration occurs because these trees continuously produce red pigments, often anthocyanins, which mask the green chlorophyll. The intensity of this permanent red can vary based on light exposure, with more sun often leading to deeper hues.
Japanese Maples (Acer palmatum) are known for cultivars with year-round red foliage. Varieties like ‘Bloodgood’ display deep purplish-red leaves from spring through summer, intensifying to crimson in fall. ‘Crimson Queen’ is a popular lace-leaf Japanese Maple, known for its finely dissected, dark red leaves that hold color well throughout the season, even in partial shade. ‘Red Dragon’ and ‘Tamukeyama’ are other examples of red-leaf Japanese Maples with consistent coloration.
The Purple Leaf Plum (Prunus cerasifera ‘Atropurpurea’) is known for its reddish-purple leaves that persist from spring until autumn. This ornamental tree often features a rounded crown and produces pinkish-white flowers in spring before leaves fully emerge. ‘Forest Pansy’ Redbud (Cercis canadensis ‘Forest Pansy’) offers heart-shaped leaves that emerge glossy ruby red in spring, transitioning to deep burgundy or purplish-green during summer. Smokebush (Cotinus coggygria), particularly cultivars like ‘Grace’ or ‘Royal Purple’, has red-burgundy foliage throughout the growing season, adding texture to the landscape.
Other Red Features of Trees
Beyond the prominent red of foliage, trees can exhibit red coloration in other parts, enhancing their visual appeal. Some trees are notable for their vibrant red bark, which becomes particularly noticeable in winter after leaves have fallen. The Red-twig Dogwood (Cornus sericea) is a prime example, with its bright red stems providing a bold contrast against snowy landscapes. Paperbark Maple (Acer griseum) also offers exfoliating bark that peels in cinnamon-red to reddish-brown curls, creating year-round interest.
Many trees produce red berries or fruits, which often serve as a food source for wildlife and add color during colder months. Female Holly trees (Ilex species) are known for their persistent red berries that remain on branches through winter. Hawthorn (Crataegus species) varieties bear clusters of small red fruits, while Crabapple (Malus species) cultivars are known for their small, red apples that can persist into winter. The Japanese Rowan (Sorbus commixta) is also known for its red berries alongside its fall foliage.
Red flowers further contribute to the diverse ways trees can display this hue. Trees like Bottlebrush (Callistemon species) produce brush-like red blooms, and certain Hawthorn varieties, such as ‘Crimson Cloud’ or ‘Paul’s Scarlet’, are grown for their red flowers. Some Dogwood cultivars, like ‘Cherokee Chief’, are known for their red or reddish-pink bracts that resemble petals in spring. Crape Myrtles (Lagerstroemia indica) also feature cultivars that produce red flowers throughout the summer.