Have you noticed the leaves of your evergreen plants blushing or even going completely red in winter? The foliage effect can be strikingly beautiful, especially on a cold, frosty day, but why does it happen, and is it cause for concern? In this short article, I’ll explain what causes the dramatic change of colour and when it might be a sign that something is wrong.
The foliage of certain evergreen plants, including Bergenia, Cryptomeria, Nandina, Rhododendron, Mahonia, and Trachelospermum, may turn from green to red, purple or bronze in winter. This phenomenon is sometimes referred to as ‘winter bronzing’. Plant breeders frequently exploit this trait, selecting cultivars that tend to produce the strongest, most eye-catching shades. I’ve listed a few below if you’d like to grow them.
The pigment responsible for the colour change is anthocyanin, the same chemical compound that makes red wine red. Anthocyanins can also appear purple or blue, colours you can sometimes detect at the very edge of your wine glass or when you cook a red cabbage, which is also packed with anthocyanins. Anthocyanins act as a plant’s natural sunscreen during periods of low temperature in a phenomenon known as photoinhibition (light limitation). The pigment protects foliage which is barely photosynthesising from being burned by sunlight it can’t harness - hence reddening is more pronounced during extremely cold, bright weather and on the parts of a plant most exposed to the sun.
Temporary reddening caused by a combination of cold and sun is not harmful to plants and is a sign they’re adapting successfully to their environment. As soon as spring arrives and they begin to grow again, the anthocyanins disperse, and the foliage returns to its usual colour. During dull, mild winters, like the one we had in 2026, reddening may not occur at all.
Should you spot foliage that’s light brown and papery, blackened or dark brown and mushy, that’s likely to be permanent frost damage. In spring, you can remove the blighted foliage and, with luck, new growth will sprout from lower down the plant.
There's a further reason foliage that’s typically green may turn red: a lack of water. Drought stress can manifest itself at any time of year. If it’s summertime, the redness is almost certainly a sign that a plant needs watering: I often see it occur in plants that have outgrown their container or are growing against a particularly hot, sunny wall. Low moisture levels increase the concentration of sugar in leaf sap, which directly fuels the production of anthocyanins as a protective measure. If you water the affected plant and wait until it gets cooler, the redness will slowly dissipate. If you take no action, the leaves may drop prematurely as a further but more extreme method of protecting itself.
Plants with a strong tendency to turn red in winter
These are some of the finest examples of evergreen plants that turn red when it’s cold. To enjoy them at their best, plant them in full sun and in a spot where you can appreciate their foliage during the winter. When planting, consider combining them with white flowers, such as hellebores and snowdrops, or with trees with white bark, such as Betula utilis ‘Jacquemontii’ (Himalayan birch), to create breathtaking contrasts.
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Bergenia 'Bressingham Ruby', 'Sunningdale' and ‘Eric Smith’ (elephant’s ears). All three varieties develop glossy burgundy or crimson tints on their large, cabbage-like leaves. These strong colours later complement bright pink flowers as they emerge in spring.
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Cryptomeria 'Elegans Compacta' (Japanese cedar). In its wild form, this is a large tree, so for the garden, this slow-growing form is a sound choice. After the first frosts, the fine, fuzzy foliage develops a purplish-fronze haze.
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Leucothoe axillaris 'Curly Red' (dog hobble). This is a great shrub for winter containers or groundcover in borders; the glossy, puckered foliage develops deep, ruby-red tones when temperatures drop. Requires acid soil or ericaceous compost.
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Nandina domestica ‘Fire Power’ (heavenly bamboo). This is another compact shrub with lime-green foliage that turns fiery orange-red and deep maroon in cold weather. ‘Fire Power’ is a dwarf variety reaching about 50–60cm in height.
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Mahonia aquifolium ‘Apollo’ (Oregon grape). This is a structural evergreen with holly-like leaves that turn from dark green to deep bronze-red or purple-red in winter. Excellent for attracting bees. The fruits, when ripe, are edible.
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Rhododendron ‘Wee Bee’ and ‘Patty Bee’. These are superb dwarf rhododendrons, and their Himalayan ancestry makes them especially hardy and suited to gardens in the north of England and Scotland. The mounded foliage develops brownish-red tones in winter, giving the appearance of rusted metal. ‘Wee Bee’ has candy pink flowers and ‘Patty Bee’ is primrose yellow.
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Trachelospermum jasminoides (star jasmine). The only climber on my list and the plant pictured at the top of this article, star jasmine, will turn red very quickly if cold, dry or otherwise stressed. If you have it planted in a pot, redness almost certainly signals that it’s time for a larger container or to plant it in the ground.