(Editor's Note: This article was originally published on October 24, 2009. Your comments are welcome, but please be aware that authors of previously published articles may not be able to promptly respond to new questions or comments.)
If you are a lover of ericaceous shrubs, then you are probably familiar with the genus Enkianthus. However, in the big scheme of things, this genus is not well known or as widely grown as it should be. Enkianthus consists of 10 species of upright shrubs, all native to Asia, from the Himalayas to Japan. The name comes from the Greek enkyos - swollen and anthos - anther, so literally means swollen anther. Their height varies, depending on the species, from 2 to 6 m. Most of the species are deciduous but there are a couple of evergreen species. The evergreen types provide year-round interest but the deciduous ones are not only grown for their modest floral display, but perhaps more so for their spectacular fall foliage. Florally, they produce nodding clusters of elegant, small, bell-shaped flowers in mid-late spring. Flowers are generally waxy-white, pink to reddish. Their branches are unusual in being produced in whorls. For the most part, they are disease and pest-free.
Details of the flowers from E. campanulatus
In the wild, these shrubs grow in mountainous regions, among forests or open shrubby meadows. Cultivation is essentially the same as for other ericaceous shrubs. They dislike alkaline soil, preferring a pH 5-6. They also dislike dry sites. To help provide the acidic moist soil they prefer, dig plenty of organic matter into their growing area. Position them in full sun to part shade, preferably in a reasonably sheltered site. Generally, they require little pruning. Being ericaceous shrubs, they combine beautifully with rhododendrons, azaleas and mountain laurels.
Variations in the fall colour of E. campanulatus
Of the 10 species, only a handful are found in cultivation, at least in North American gardens. Perhaps the most common in cultivation is the Japanese species E. campanulatus, commonly called the red-vein enkianthus. This species grows to a height of 4 to 5 m and is the hardiest species, rated to zone 5. There are many named cultivars, several having Japanese names such as 'Sinsetu', 'Miyamabeni' and 'Akatuki'. The wild flower colour is off-white with red veins but the named selections come in pink or red shades. Some cultivars turn glowing-red in autumn, while others take on yellow to orange shades. Perhaps the most popular cultivar is 'Red Bell' whose flowers are pinkish-red and fall colour is brilliant scarlet. 'Showy Lantern', 'Princeton Red Bells', 'Sikokianus' and 'Hollandia Red' are very similar and equally as exquisite for both flowers and fall colour. 'Albiflorus' has pure white flowers without any red veins while 'Renoir' has yellowish flowers with pink tips and a mix of yellow, orange and red fall colour.
Above are some named selections including 'Showy Lantern', 'Princeton Red Bells' (above left and right) and 'Red Bells' (below and introduction picture)
Next in popularity is E. cernuus, a more dwarf version of E. campanulatus, reaching about 3 m. The variety rubens has glowing red flowers. This was is not quite as hardy, being rated for zone 6. It also has spectacular red fall colour. The giant of this genus is E. deflexus which can reach 9m. The current years stems of this species are vivid red. Enkianthus serrrulatus is an uncommon species but has the largest flowers of any Enkianthus. It reaches about 6 m. For the small garden, E. perulatus is ideal as they only attain a height of 1.2-1.8m. These last two species have ivory-white flowers and are the earliest-blooming species, blooming just as the leaves emerge in spring. These above species are all rated for zone 6. In mild zones (zone 8) you might try to find the evergreen species E. quinqueflorus. This one reaches 1.8 m with delightful pale pink flowers and deep pink calyxes, lending the flowers a two-tone effect.
Above are E. perulatus in spring and fall; below are details of E. cernuus var. rubens
If you have success with rhododendrons and mountain laurels, then Enkianthus are a must to provide added interest to the ericaceous border. Now your challenge is to find them! Perhaps not an easy task but well worth it.
I would like to acknowledge the following people for the use of their pictures: alph (fall E. campanulatus), growin (E. campanulatus flowers), gmarr ('Red Bell'), goldenfish (E. cernuus var. rubens), secludedgardens (E. campanulatus flowers) and victorgardener ('Showy Lanterns', 'Princeton Red Bells', E. perulatus).