<em>Enkianthus</em>, campanulate andromeda: planting, growing, caring for

Description and botany

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

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

With slow growth, this bush develops gradually to form, depending on species, a small tree with an erect habit, often narrow, sometimes spreading or globular, bushy and well ramified from the base. In campanulate enkianthus, shoots grow in whorls, giving the bush a well-balanced, harmoniously tiered set of branches. The largest Enkianthus will, after many years, reach on average 2 to 4–5 m in all dimensions. Dwarf varieties exist not exceeding 60 cm to 1.20 m in height, modest sizes that allow container culture and training as bonsai or cloud-pruned specimens.

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

From April to June, sometimes before leafing, Enkianthus is covered with , borne in umbels or in fine pendulous clusters at shoot tips. The flowers, 0.5 to 2 cm wide and formed of 5 fused petals, sway gracefully at the end of long pubescent pedicels sometimes lightly raspberry-pink.

Delicate bell-shaped flowering of campanulate andromeda

Grouped in corymbs of 5 to 20 beneath the leaf fan, they display a slightly waxy texture. Infinitely delicate, these swollen corollas set off by a calyx of acid green or pink-tinged green, range across shades of cream-white and pink, and even a red so bright it evokes currant clusters. Uniformly coloured flowers are also subtly veined with carmine or white striations depending on variety, offering gentle tonal variations.

Slightly scented, this exquisite bloom of melliferous and nectariferous bells recalls Pieris japonica and lasts about a month.

After flowering, brown, winged, ovoid capsule fruits appear and often persist through winter.

Dense, deciduous foliage is composed of leaves arranged in clusters alternately at shoot tips that can be 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 above or beneath and form denser groups at branch tips.

Enkianthus campanulatus : fruiting and autumn foliage

This attractive foliage, bright or bluish-green in spring, takes on a magnificent autumn dress. Leaves then show beautiful autumn colours ranging from gold to yellow-orange and to scarlet red before falling.

Enkianthus is perfectly hardy and tolerates temperatures down to -15°C, often lower, provided planted in a sheltered spot. Originating from damp woods, it prefers semi-shaded positions in the garden and requires acid, lime-free soil as it is a plant of heather soil.

Use it equally well in a mass planting with other ericaceous shrubs, in the woodland understorey, or in a large container on a terrace.

Main species and varieties

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

Our favourites

Enkianthus campanulatus

This is the most widespread species! Small in size and versatile, it is no less remarkable with its bright green foliage turning red in autumn! Ideal for small spaces, in borders as well as on terraces!

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

See the product sheet

Enkianthus campanulatus Red Bells

Brilliant flowering: small flowers veined and striate with raspberry-red on a pale pink background, and its beautiful autumn colours from yellow to orange are a delight! This cultivar suits small gardens and pots.

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

See the product sheet

Planting

Where to plant Enkianthus?

Very hardy, Enkianthus tolerates temperatures down to -15°C to -20°C, sometimes even lower, without failing. 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 overly dense shade, it needs light to flower well and to develop attractive autumn colours. It will establish less easily south of the Loire, as it dislikes scorching sun and drought. It can tolerate a few hours of sun in the morning or late afternoon only if the soil remains cool.

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

This is an acidophilous bush that above all dislikes lime and requires acidic soil, ideally close to heather soil: plant in a cool, well-drained, light, humus-bearing and non-calcareous soil.

Slow-growing and compact, this bush is ideal as a specimen for small, well-kept gardens and urban gardens. Very versatile, Enkianthus is used equally well in mixed 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 shaded terrace.

Plant taller varieties in a sheltered woodland spot to thicken a hedge; dwarf varieties (Enkianthus perulatus ‘Compacta’, Enkianthus campanulatus ‘Hollandia’) are suitable for a cool, rockery-style setting or for containers, styled as bonsai.

When to plant Enkianthus?

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

How to plant Enkianthus?

In the ground

Like all heather-soil shrubs, Enkianthus cannot tolerate calcareous soil. In all cases, it is preferable to add some heather soil when planting (pH should be below 6.5).

If soil is too calcareous, replace excavated earth with a mix of heather soil and leaf mould, plant preferably in a container or accept that this acidophilous nature cannot easily be changed. Choose a less lime-sensitive bush unless you are prepared to add heather soil regularly in varying amounts. Avoid areas where water stagnates in winter: plant on a mound if necessary.

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

Planting a heather-soil bush correctly is easy if you follow our advice!

Growing in a pot

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

Maintenance, pruning and care

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

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

Possibly each spring, top-dress around base with well-rotted compost and heather soil.

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

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

Smaller varieties such as cultivars of Enkianthus perulatus can be shaped as desired and trained as small trees, as bonsai, or even cloud-pruned. Discover more tips in our sheet “how to prune spring-flowering bushes“.

Cultivated under good conditions, no pests are known for Enkianthus. If soil is limestone, however, it may develop chlorosis, which is characterised by yellowing of leaves: consider before planting adding heather soil and water only with rainwater.

Multiplication

Propagation of Enkianthus can be done by sowing in spring, although this technique is rather delicate. Layering is also possible in late summer to multiply Enkianthus, but you must be patient, because root development is very slow. That is why, we recommend propagation by cuttings in summer (August–September), once flowering has finished, on semi-woody shoots.

By semi-ripe cuttings

• Take shoots 10 to 20 cm long 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 potting compost and sand
• Firm down
• Mist cuttings regularly with a spray
• Pot them on into buckets as soon as they have formed roots
• Overwinter them frost-free at 20 °C in a bright place but sheltered from direct sun
• Plant out in ground or in a pot the following spring

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

Associate

Enkianthus offers two beautiful seasons: spring when it is covered with delicate, pastel-hued bells and autumn when its foliage turns gold, orange or deep red, allowing wonderful pairings in semi-shaded areas of the garden.

Its flowering is inspiring in a romantic garden, whether pink or white, to which it adds freshness and delicacy. Trained in a cloud form like a bonsai, this bush will complete a zen and Japanese-inspired garden with Japanese azaleas, bold 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’ beneath the canopy of 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, heucheras, 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 daffodils.