It's the nature of perennial gardens to be ever changing with plants coming in and out of bloom all summer. Add continuity to your perennial border by including plants with distinctively coloured leaves. Perennials with burgundy-red foliage add drama to the border and make a background for plants with pink flowers or bright yellow-green leaves.
The Science Behind the Color
Most plants have green leaves because of high concentrations of chlorophyll, the substance plants use for photosynthesis. However, there are two other pigments in leaves: carotenoids and anthocyanins. Plants with higher-than-normal levels of carotenoids, such as golden creeping Jenny or yellow barberries, appear yellow or yellow-green, and leaves with high levels of anthocyanins, like coral bells and sedums, are red. The chlorophyll is still there, but the other pigments mask the green.
Burgundy-Leaved Perennials for Sun
One of the nicest burgundy perennials for sun is Penstemon digitalis "Husker Red," which is recommended by the Perennial Plant Association. The red leaf colouration is darkest in full sun. The plant grows well in light shade, but the colouring is less intense. Husker Red's burgundy leaves are topped by white flower stalks in early summer. There are many red and burgundy varieties of stonecrops (Sedum) available. Morchen, Vera Jameson and Fuldaglow are all easily available cultivars with deep-burgundy foliage. The dwarf goat's beard's (Aruncus aethusifolius) foliage emerges green but turns burgundy-red as the season progresses. Keep the plants well-watered.
Burgundy-Leaved Perennials for Shade
Coral bells (Heuchera) are one of the most common red-leaved plants for shade gardens. Plant breeders worked on these American wildflowers for decades producing a range of brightly coloured, variegated leaves. Place Purple is an older variety with dark burgundy leaves. Its large size and dependable red colouring make it a reliable staple in shaded perennial beds. Consider the Plum Pudding, Ruby Ruffles and Chocolate Ruffles cultivars. Most red-foliage Heucheras have white flowers. Epimedium grandiflorum "Rose Queen" and Ajuga reptans "Jungle Beauty" are two shady groundcovers with burgundy-red leaves.
Perennials with Burgundy Fall Color
Perennial foliage changes colour in the fall. Pigsqueak (Bergenia cordifolia) is a large-leafed perennial with several red-tinged cultivars including Bressingham Ruby and Evening Glow. Bergenia's red colouration is more pronounced in cool weather. Dwarf plumbago (Ceratosigma plumbaginoides) is a fast-spreading, perennial groundcover with green leaves and bright-blue flowers in summer. When the temperature drops in fall, the foliage turns red, contrasting with the flowers. Most Japanese anemones (Anemone x hybrida) have dark red fall colouration.
Why Red Plants Lose Their Red Color
If you put a sun-loving, red-leafed plant in the shade, it loses some of its red colour because the plant produces less anthocyanin and more chlorophyll compensating for the low light levels. Moving the plant to a brighter spot restores the red leaf colour.