<em>Styrax</em>, aliboufier: to plant, to grow, to care for

Description and botany

Of family Styracaceae, Styrax or Aliboufier, also called “silver-bell tree”, is a bush native to open woodland margins and riverbanks of Asia, notably Japan and China, but also found in North America and around Mediterranean basin. Genus Styrax includes more than a hundred species of bushes or small trees, deciduous or evergreen. Only three are commonly found in our gardens: Styrax officinalis, which grows naturally in southern France, S. obassia or “large-leaved Styrax”, and Styrax japonicus (S. japonica) or Japanese styrax, with numerous cultivars such as ‘Fargesii’, ‘Pendula’ or ‘Pink Chimes’.

This bush, with single or multiple trunk, has a bushy, upright or rounded habit, often spreading gracefully, sometimes weeping (Styrax japonica ‘Pendulus’). Some recent cultivars such as ‘June Snow’ even show a columnar habit. Branches of Styrax most often tend to grow horizontally, giving a very elegant, layered silhouette. Depending on variety, it forms small trees or large bushes. Smallest styrax rarely exceed about 1 to 2 m in height; compact, they can be planted anywhere, even in a pot. Larger specimens can reasonably reach up to 6–7 m, rarely more in our regions. Styrax has moderately fast growth and notable longevity, often living more than 100 years.

Trunk shows attractive smooth grey-brown bark that fissures with age.

Styrax develops magnificent foliage from spring to autumn. Deciduous alternate leaves are elliptical, ovate or obovate and pointed, with a strongly marked central vein and sometimes finely dentate margins. Large-leaved Styrax (Styrax obassia) is distinguished by large, almost round leaves ending abruptly in a point. Leaves, a tender to olive green slightly glossy above and pubescent beneath in spring, turn yellow or orange-red in autumn, extending bush’s ornamental interest. Some cultivars display near-black purple foliage, such as Styrax japonica ‘Evening Light’.

Styrax officinalis – botanical illustration by Pierre-Joseph Redouté

Leaves measure 3 to 20 cm long and point upwards, providing contrast with bush’s bright flowering display.

In early summer, from May to June, bush produces a dense, delicate flowering best admired from beneath! It bears an abundance of small pendulous, fragrant bell-shaped flowers, gathered in small clusters of three to six at tips of current-year shoots. Their corolla, about 1 to 2 cm wide, is formed of five petals, most often pure white, sometimes tinged with pink, from which a bouquet of stamens with golden anthers emerges. They recall flowering of Halesia carolina. Styrax japonica ‘Pink Chimes’ is one of few varieties to offer pink flowers.

These campanulate bells are melliferous and exhale an intense, slightly sweet, vanilla-like perfume, prized in perfumery and incense making.

By mid-summer they give way to small pruinose fruits, ovoid fleshy drupes of a whitish-green hue containing a brown seed.

Hardy, Aliboufier can withstand temperatures around -15°C, sometimes lower, and adapts to most regions, provided it is given a sheltered position away from cold winds to protect flower buds from late frosts.

Easy to grow, Styrax thrives in part-shade or sun in a well-drained soil, preferably acidic, rich and humus-bearing. It adapts well to any good garden soil so long as it remains cool, not very calcareous and well drained.

Its compact yet elegant habit and rather slow growth make Styrax a bush suited to natural gardens, even small spaces, forming attractive focal points.

It can be grown as a solitary specimen in centre or rear of a border or glade, or in groups, in a mixed hedge combined with heather-soil bushes. Some modestly sized varieties are well suited to cultivation in a pot on a terrace or near entrances.

Styrax resin, known as “benzoin”, has been prized since Antiquity for aromatic and medicinal properties, notably antiseptic, antispasmodic and wound-healing. This aromatic substance is also used in famous incenses and perfumes. Benzoin is also an ingredient in production of Armenian paper.

Main species and varieties

Of the roughly one hundred species of the genus, Styrax officinalis, S. obassia and Styrax japonicus or S. japonica, which declinate into numerous dwarf, weeping or pink-flowered cultivars, are the species most commonly grown.

Our favourites

Styrax japonica

Easy to grow, hardy, with a very graceful spreading habit. Manageable size suits small gardens and cultivation in pots.

• Flowering time July, August
• Height at maturity 4 m

See the product sheet

Styrax obassia

It may be slightly less hardy and is notable for its large leaves. Ideal along a path, on a terrace or by the house entrance to enjoy its delicate scent.

• Flowering time June, July
• Height at maturity 6,50 m

See the product sheet

Planting Styrax

Where to plant Styrax or silver-bell tree?

With good hardiness, Styrax can easily withstand temperatures of -15 °C to -20 °C and acclimatises throughout France, except perhaps in Mediterranean climate, which is a little too hot and dry in summer.

However, avoid drying, icy winds that can scorch foliage and damage flowers, which are sensitive to late frosts. Plant in a sheltered position in sun, if sun is not too scorching, or in partial shade. It can tolerate full sun except during hottest hours of day. If you live in Mediterranean region, prefer a shaded situation.

Easy to grow, Styrax thrives in any good, fresh, well-drained garden soil, preferably non-calcareous and even slightly acidic. In all cases, it is advisable to add a little heather soil at planting.

This bush generally becomes as wide as tall: allow it a generous, open spot.

Plant in a small grove, in an informal hedge or as a specimen; it also makes attractive centrepieces for borders. The smaller varieties of Styrax are suitable for container culture on the terrace to enjoy its delicate fragrance; this is also a good solution if ground is too calcareous.

When to plant Styrax or snowbell?

Planting Styrax is best done in autumn, from September to October, to encourage rooting before winter. Spring planting is also possible once risk of frost has passed.

How to plant Styrax?

In open ground

For successful planting of your Styrax, also see our advice sheet: Planting heather soil bushes — WHERE AND HOW?

• Dig a hole about twice size of root ball
• Amend garden soil with some well-rotted compost, one third heather soil and one third coarse sand
• Place bush, stake it, then backfill hole and firm gently
• Water well and mulch soil with pine bark to help retain coolness in summer
• Continue to water regularly for first three years

Styrax japonica: flowers and fruits

In pots

You can also grow Styrax in pots: choose the most compact varieties. Plant in a mix of potting compost, sand and heather soil. Styrax in pots will require more frequent watering than in open ground.

Maintenance, pruning and care

Styrax is an easy-to-maintain bush. During first three years after planting, and especially in periods of drought, monitor its water needs by watering regularly as soon as the soil dries at the surface. Soil should remain moist: it is preferable to mulch the base every year in spring to retain moisture.

Styrax appreciates humus-bearing soils, which is why we recommend adding a little well-rotted compost each spring by lightly forking in at the base of the trunk.

If you live in a cold area, do not hesitate to cover it with a horticultural fleece to protect young shoots from frost.

Pruning is not essential, except to rebalance the branches or remove crossing or badly placed branches, or to remove dead wood. It should be carried out in February–March, before vegetation resumes.

Styrax has no pests or diseases.

Multiplication

Sowing Styrax seeds is possible but this delicate technique should be reserved for experienced, patient gardeners, especially as double stratification of seeds is required. Prefer propagation by cuttings in August–September, once flowering has finished, on semi-ripe shoots.

• Take cuttings 10 to 20 cm long while still soft
• Remove leaves from base of stems
• Plant them in pots with potting compost mixed with sand
• Keep them moist by watering regularly
• Overwinter them frost-free
• Plant them out in open ground the following autumn

Pairing Styrax in the garden

Styrax or silver-bell tree is a bush that offers two seasons of ornamental interest: in early summer when it is covered with its white flowering and in autumn when its leaves turn coppery orange and golden yellow.

With its elegant silhouette, it creates pretty focal points in natural gardens, white gardens and romantic gardens. Its delicate white bells will stand out beautifully against the evergreen foliage of campanulate Andromedas, Forsythias, Leucothoe and Viburnums.

An idea for a planting combination: Styrax japonica, Nepeta faassenii, Phlomis russeliana, Tulip ‘Queen of the Night’, Lupin ‘Gallery Blue’, Rose ‘Fantin Latour’ and Achillea ‘Moonshine’

In a grove, pair it with Halesias, witch-hazels, Magnolias, Mahonias and Fothergillas. In a cool, romantic border, surround its trunk with part-shade perennials such as Epimediums, Phlox divaricata, Melittis, hardy geraniums, Tiarellas, Solomon’s seals, peonies or Dicentra, which will accompany its white flowering.

For a white/silver harmony, place it near the silvery foliage of Hostas and Brunneras.

This bush, favouring acidic soils, is easily paired with ericaceous plants such as Camellias, Azaleas, Rhododendrons, Kalmias, Skimmias, Japanese Andromedas, Sarcococcas or Daphnes. Plant a few heathers alongside them.

It will be very effective alongside shrubs with coloured autumn foliage such as Caramel tree, Acer or Cornus, with which it will harmonise perfectly in tone.