<em>Enkianthus</em>, campanulate andromeda: to plant, to grow, to care for

Description and botany

Native to woods and thickets of Japan and southern China, notably Taiwan, Enkianthus is a deciduous bush belonging to family Ericaceae, like heathers, rhododendrons and andromedas to which it is closely related. Genus Enkianthus comprises about ten species of shrubs or small trees, including Enkianthus campanulatus, also named “campanulate andromeda”, which is most widely grown and occurs in various forms such as Enkianthus campanulatus var. palibinii and several cultivars like ‘Red Bells’. Enkianthus perulatus (probable synonym of E. japonicus) or “white enkianthus“, a small, more compact species, is also commonly grown.

Enkianthus quinqueflorus, a species with large leaves and flowers, Enkianthus chinensis and Enkianthus cernus are rarely seen in gardens.

Slow-growing, this bush develops gradually to form, depending on species, a small tree with an erect habit, rather narrow, sometimes spreading or globose, bushy and well ramified from the base. In campanulate enkianthus, shoots grow in whorls, giving the plant a well-balanced, harmoniously tiered branching. The largest Enkianthus will eventually reach, after many years, about 2 up to 4–5 m in height and spread. There are dwarf varieties not exceeding 60 cm to 1.20 m in height, compact sizes suitable for pot culture and pruning as bonsai or cloud-pruning.

Many years are required to see it form a true small tree: patience rewarded by a long lifespan in the garden and a delicate, distinctive spring flowering.

From April to June, sometimes before leaf emergence, Enkianthus is covered with a multitude of campanulate or urn-shaped bells, borne in umbels or fine pendulous clusters at shoot tips. Flowers, 0.5 to 2 cm wide and made of 5 fused petals, sway gracefully at the end of long pubescent pedicels that are sometimes slightly raspberry-tinged.

Delicate bell-shaped flowering of campanulate andromeda

Grouped in corymbs of 5 to 20 beneath the leaf fan, they offer a slightly waxy texture. Infinitely delicate, these swollen corollas set in an acid-green or pinkish-green calyx range across all shades of creamy-white and pink, and even a red so bright it recalls clusters of currants. United, they are also subtly veined with carmine or white striations depending on variety, offering gentle shades of colour.

Lightly scented, this exquisite bell flowering, melliferous and nectariferous, recalls Pieris japonica and lasts for around a month.

After flowering, brown fruits in the form of ovoid, winged capsules appear and persist through winter.

Dense deciduous foliage consists of leaves arranged in clusters, alternately at shoot tips that are sometimes reddish, 2 to 7 cm long by about 2 cm wide, lanceolate, elliptical to ovate, very finely dentate and veined. Leaves are matte, glossy or sometimes downy on upper surface or underside and form denser leaf clusters at branch tips.

Enkianthus campanulatus : fruiting and autumn foliage

This pretty foliage, bright green or blue-green in spring, takes on a magnificent autumnal display. It then adopts fine autumnal shades ranging from gold and yellow‑orange to scarlet red before falling.

Enkianthus is perfectly hardy and tolerates temperatures down to -15 °C, sometimes lower, provided it is planted in a sheltered position. It is therefore widely cultivated in France. Native to moist woods, it prefers semi‑shaded garden positions and requires only acidic, lime‑free soil as it is a heather-soil plant.

It is used equally well in mixed borders with other heather-soil bushes, in woodland understorey, and in a large container on a terrace.

Main species and varieties

Campanulate Andromeda is the tallest species and most widespread in our gardens. It has notably given rise to remarkable cultivars with subtly bicoloured flowers and to a hybrid form, Enkianthus campanulatus var. palibinii.

Our favourites

Enkianthus campanulatus

It is the most widespread species! Compact and versatile, it fits anywhere yet remains remarkable with bright green foliage that reddens in autumn. Ideal for small spaces, in borders or on terraces!

• Flowering time June, July
• Height at maturity 1,50 m

See the product sheet

Enkianthus campanulatus Red Bells

Its dazzling flowering — small flowers veined and striate with raspberry red on a pale pink background — and its lovely autumn shades from yellow to orange are a delight! This cultivar suits small gardens as well as containers.

• Flowering time June, July
• Height at maturity 2,50 m

See the product sheet

Planting

Where to plant Enkianthus?

Very hardy, Enkianthus withstands temperatures down to -15°C to -20°C, sometimes even lower, without faltering. However, planting sheltered from cold, drying winds is recommended; young shoots can be sensitive to late frosts.

This bush prefers semi-shaded positions, sheltered from direct sun, under dappled shade of large trees. Avoid dense shade, however, as it needs light to flower well and to develop attractive autumn colours. It will establish less easily south of the Loire, because it dislikes scorching sun and drought. It can tolerate a few hours of morning or late-afternoon sun only if soil remains cool.

Easy to grow, it only needs coolness and acidity to thrive.

This is an acidophilous bush that cannot tolerate lime and requires acidic soil, ideally close to heather soil: plant in a cool, well-drained, light, humus-bearing, non-calcareous soil.

Slow-growing and compact, this bush is ideal as a specimen for small, tidy gardens and urban gardens. Very versatile, Enkianthus can be used in shrub borders with other heather-soil shrubs, with spring-flowering perennials, in a clump at woodland edge surrounded by spring bulbs, or in a pot on a shady terrace.

Plant taller varieties in a sheltered, wooded spot to thicken a hedge; dwarf varieties (Enkianthus perulatus ‘Compacta’, Enkianthus campanulatus ‘Hollandia’) are suitable for a cool rockery or for pots, trained as bonsai.

When to plant Enkianthus?

Plant Enkianthus ideally in autumn from September to November or in spring, March to May, outside frosty periods.

How to plant Enkianthus?

In open ground

Like all heather-soil bushes, Enkianthus cannot survive in calcareous soil. In all cases, it is preferable to add some heather soil at planting (pH should be below 6.5).

If soil is too calcareous, replace excavated soil with a mix of heather soil and leafmould, plant preferably in a pot or simply avoid fighting its acidophilous nature. Choose a bush less intolerant of lime rather than having to add heather soil regularly in more or less large quantities. Avoid areas where water stagnates in winter: plant on a mound if necessary.

• Dig a planting hole about two to five times wider than rootball
• Add gravel, pumice or a good bed of clay pebbles to bottom of hole to ensure good drainage
• Place your Enkianthus at collar level, in a mix of loamy soil, turf, heather soil and leafmould
• Backfill and firm gently
• Water thoroughly
• Spread a good layer of bark mulch or pine needles at base of bush
• Water regularly during first year with rainwater

How to plant a heather-soil bush correctly, it’s easy if you follow our advice!

Growing in a pot

You can also grow Enkianthus in a pot, its slow growth making this culture possible. We recommend choosing dwarf varieties. Choose a container large and deep enough (30 to 40 cm diameter), then plant your bush in a free-draining mix of garden soil, turf and 50% genuine heather soil. Careful monitoring of watering will be necessary. Mulch the base or plant small perennials such as small cyclamens, brunnera, dodecatheon or hardy geraniums to help retain coolness.

Maintenance, pruning and care

Once well established in non-calcareous soil suited to its nature, the Enkianthus will need little attention apart from regular watering, especially during the first two summers after planting. It must never lack water; it needs moist, cool soil in summer but dislikes excess water in winter. Water with non-calcareous water; prefer rainwater. Enkianthus grown in containers require more frequent watering.

In spring, spread a layer of organic mulch (bark or pine needles, layer of dead leaves, fronds of ferns), renewed each year, to keep roots cool during summer heat and reduce watering.

Possibly each spring, topdress the base with well-rotted compost and heather soil.

Remove faded flowers after flowering to prevent seed formation that weakens the plant.

Growing slowly, pruning is unnecessary but on larger varieties it will help rebalance their shape and limit height. Pruning is carried out after flowering. Only intervene to remove any dead or poorly placed branches.

The smaller varieties such as cultivars of enkianthus perulatus can be shaped as desired and trained as small trees, as bonsai, or even pruned into cloud shapes. Discover more advice in our guide to “pruning spring-flowering bushes“.

When grown in good conditions, Enkianthus has no known pests. If soil is calcareous, it may nevertheless develop chlorosis, characterised by yellowing of the foliage: before planting, consider adding heather soil and water only with rainwater.

Multiplication

Multiplication of Enkianthus can be achieved by sowing in spring, however this technique is fairly delicate. Layering is also possible at end of summer to multiply Enkianthus, but patience is required, as root development is very slow. That is why, we recommend propagation by cuttings in summer (August–September), once flowering has finished, using semi-woody shoots.

By semi-ripe cuttings

• Take 10–20 cm shoots with a heel
• Cut cleanly just below a leaf
• Remove leaves from lower part of cuttings
• Keep leaves on upper part
• Plant them in a light, free-draining substrate of compost and sand
• Firm gently
• Mist cuttings regularly with a sprayer
• Pot them up into buckets as soon as roots have formed
• Overwinter frost-free at 20 °C in a bright spot but sheltered from direct sun
• Plant out in ground or in a pot the following spring

To learn more, read our tutorial : How to propagate Japanese Andromeda?

Associate

Enkianthus offers two beautiful seasons: spring when it is covered with delicate campanulate flowers in pastel tones and autumn when its foliage turns gold, orange or deep red, allowing wonderful pairings in partly shaded areas of garden.

Its flowering is inspiring in a romantic garden, pink or white to which it brings freshness and delicacy. When trained as a cloud in bonsai style, this bush will complement a zen, Japanese-inspired garden with Japanese azaleas, architectural grasses and phormium.

An idea for a pairing in acidic soil and a shaded spot: Enkianthus campanulatus, Meconopsis betonicifolia, Dryopteris cycadina (syn. atrata) and Hosta ‘Halcyon’ under the canopy of a Halesia carolina

It naturally finds its place in a large border surrounded by other heather soil bushes, and will be magnificent alongside Pieris, Rhododendrons, Camellia, Kalmia, azaleas and other closely related plants such as Leucothoe, hydrangeas or skimmia.

It pairs easily with shade-loving perennials such as ferns, Brunnera, heuchera, Epidemium, pachysandra or hostas.

In spring, create fresh, romantic scenes and surround its base with spring-flowering bulbs such as Cyclamen coum, lilies, pink tulips, white narcissi.