Eleutherococcus, Acanthopanax: planting, growing, and maintaining

Botany

Eleutherococcus (formerly known as Acanthopanax) belongs to the Araliaceae family, which includes over 1,500 species, just like Aralia elata (“Angelica tree”), with which it is closely related, ivy (Hedera helix), and ginseng (Panax ginseng), as well as Fatsia. This Asian shrub is native to central and western China, the Philippines, and Japan. This plant prefers temperate zones, where it grows in underbrush, humid forests, and on mountain slopes. Its adaptation to these environments allows it to tolerate a wide range of climatic conditions.

The genus comprises about thirty species of spiny shrubs and trees, the most well-known being Acanthopanax or Eleutherococcus henryi (Henry’s Eleutherococcus), Acanthopanax sieboldii, now called Eleutherococcus sieboldianus (Siebold’s Eleutherococcus), valued for their ornamental qualities, as well as Acanthopanax senticosus (Eleutherococcus senticosus), sometimes referred to as “Japanese ginseng” or “Siberian ginseng,” often used in herbal medicine.

The palmate foliage of Eleutherococcus senticosus

The size of Eleutherococcus varies depending on the species and varieties, ranging from 1.50 m for dwarf varieties to about 2-3 meters in height. In its natural environment, it can reach up to 3.50 m tall. It has a spreading form and a bushy habit, both dense and elegant. The arching branches are densely branched, and armed with sharp, deterrent thorns, giving it a compact and bushy appearance that is interesting in defensive hedges, earning it the nickname “Devil’s Bush.”

The deciduous foliage appears in spring, quite late. Palmate and ornamental, it is typical of the Araliaceae family, having a lush appearance. Each leaf is divided into five leaflets with dentate margins, arranged in a star shape around a central petiole that is sometimes spiny. They unfold at the tips of the branches, creating an umbrella effect. They often have a slightly leathery texture and a rough upper surface. They measure 3 to 8 cm long. Eleutherococcus henryi is distinguished by larger and more numerous leaves. Each leaf can have up to nine leaflets, which are elongated and pointed, sometimes measuring up to 15 cm long. The leaves are usually green, grey-green, turning golden yellow in autumn before falling. Some varieties, such as ‘Acanthopanax sieboldii ‘Variegatus’, stand out with their bright cream-variegated foliage.

The flowering of Eleutherococcus

The flowering of Eleutherococcus generally occurs between June and September, earlier or later depending on the climate. It appears in the form of small flowers grouped in umbels 2 to 3 cm in diameter, at the tips of the branches. The flowers are cream-white to pale yellow, relatively inconspicuous due to their small size, arranged in tight, light-looking clusters. Each flower consists of five petals surrounding a centre of prominent stamens. Although unscented, the flowers are nevertheless melliferous, attracting pollinating insects, particularly bees.

Only female plants have the ability to produce fruits. Female flowers must be pollinated by pollen from male flowers: once pollination is successful, female flowers give way to small oval fruits that turn black when ripe, resembling those of ivy. These shiny berries, arranged in tight clusters, often grouped into balls about 5 cm in diameter, may persist until winter. Each contains five yellow seeds.

The fruits of Eleutherococcus

Main species and varieties

Acanthopanax henryi - Henry's Aralia

A beautiful deciduous bush from the collection that is pleasant to look at, despite its strong thorns.

• Période de floraison September, October
• Hauteur à maturité 2 m

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Acanthopanax henryi Nana - Henry's Aralia

A dwarf version of the previous one! Slightly thorny, very hardy and quite accommodating.

• Période de floraison July, August
• Hauteur à maturité 1,30 m

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Acanthopanax sieboldianus Variegatus

A graphic variety, very bright, ideal for landscaping shaded areas of the garden.

• Période de floraison July, August
• Hauteur à maturité 2 m

See the full description

Planting

Where to plant?

Hardy down to -18 °C, Eleutherococcus or Acanthopanax can be grown in the ground in many regions. However, it is advisable to plant it in a location sheltered from cold, drying winds to protect its foliage and young shoots. A spot near a wall facing east or north, or under the canopy of larger trees, can provide this natural protection. The ideal exposure is partial shade or light shade, although it can also tolerate denser shade. In warmer regions, a location with partial shade, particularly out of direct afternoon sun, is essential to prevent leaf burn. In cooler areas, a sunnier exposure may be beneficial to encourage flowering and fruiting.

Very accommodating, although it adapts to different soil types, it will thrive in any good garden soil that is well-drained and rich in organic matter. As a good forest plant, a humus-bearing soil that remains cool in summer will support its growth. It tolerates dry shade well. It only fears scorching exposures and waterlogged soils.

It is perfect for planting at the edge of a thicket, in woodland clearings, in a shrub border, or in a free-standing or trimmed hedge, whether defensive or not. With its highly ornamental foliage, it fits perfectly into a naturalistic, Japanese, or exotic garden. Variegated varieties are ideal for bringing brightness to shaded corners of the garden.

When to plant?

You can plant Eleutherococcus in autumn (September to October) or in spring (March to May), outside of frost or extreme heat periods.

How to plant?

• Loosen the soil to a depth of about 30 to 40 cm to facilitate rooting. If the soil is heavy or clayey, incorporate compost or potting soil to improve drainage and soil structure.
• Soak the root ball in water for a few minutes to moisten it.
• Dig a hole twice as wide and deep as the root ball.
• Place the Eleutherococcus in the centre of the hole, ensuring that the top of the root ball is level with the collar.
• Fill in and then lightly firm the soil around the root ball to eliminate air pockets without compacting excessively.
• Water generously after planting to help the plant establish. A mulch can be spread around the bush to retain moisture and protect the roots.
• Continue to water regularly.

Eleutherococcus sessiliflorus

Maintenance, pruning and care

The maintenance of Eleutherococcus is relatively simple. It is a robust and low-maintenance bush that will appreciate regular watering, especially during the first few years after planting and in dry periods. Mulching at the base will help retain soil moisture. In spring, you can apply organic fertiliser or well-decomposed compost to the stump to enrich the soil, and incorporate it superficially by simple raking.

Eleutherococcus is not susceptible to diseases and pests.

Pruning

Pruning Eleutherococcus is generally not necessary. However, a light pruning can be carried out to encourage branching, limit its spread, or to remove dead, damaged, or diseased branches. Pruning stimulates the appearance of new shoots. The best time to prune is at the end of winter or the beginning of spring, in March, before the growth resumes, to allow it to branch and limit its spread. It is not afraid of repeated pruning, which is beneficial in cases of excessive growth. You can cut it back severely every 4 or 5 years.

Eleutherococcus is a bush that tends to sucker. These suckers can quickly spread and colonise the surrounding space until they form a dense groundcover or an impenetrable hedge. To remove them, cut them at the base, as close to the root as possible, using a sharp pruning shear.

Multiplication

We recommend propagating Acanthopanax by taking suckers that develop on the roots of the mother plant to obtain new plants. Sowing is also possible if you have access to seeds from Eleutherococcus, provided your tree bears fruit; however, this method is more tedious and unpredictable.

Taking Suckers

To propagate the bush, simply:

• Dig up well-formed suckers at the end of winter, around February or March, taking care to preserve part of the roots.
• Replant the young shoots directly in another part of the garden or in pots, where they will establish quickly.

Sowing

You can harvest the fruits to collect the seeds they contain. They must be cold stratified by placing them in the refrigerator for about 3 months. You can then sow them in a mixture of potting soil and sand at a temperature between 20 and 30 °C. You can transplant the young plants as soon as they have 6 to 8 leaves. Allow them to strengthen for a year in pots before transplanting them to their final place in the garden.

Association

The large palmate leaves of Eleutherococcus create beautiful atmospheres tinged with exoticism in dark areas of the garden, for example. In a somewhat “jungle” composition, it can be paired with other well-developed and lush foliage, such as that of Aralia elata, Gunnera, and Fatsia japonica, for interesting contrasts.

In a very natural undergrowth setting, Eleutherococcus can be planted near hostas, ferns, and Paris polyphylla, a beautiful shade perennial with very graphic foliage, plants that, like it, enjoy semi-shaded spots and soils rich in organic matter, always a bit cool.

It also works wonderfully in a trimmed or free-form hedge with other shrubs as easy-going as it is, such as privets or Ligustrum, bush honeysuckles, or hedge honeysuckles (Lonicera xylosteum).

Botanical roses and white spireas will also be good companions in a natural and wild shrubbery. Japanese maples, with their delicate and colourful foliage, also harmonise well, especially if you are looking to create Asian-inspired scenes. Low, gracefully arching grasses like Carex or Hakonechloa can thrive alongside it to brighten and cover the soil in the shaded corners of the garden.

Eleutherococcus will integrate beautifully into an exotic garden, with lush foliage and spectacular blooms. Eleutherococcus trifoliatus, Fatsia japonica, Crinum powellii, Hedychium gardnerianum (photo: J.J. Harrison) and Gunnera manicata

Did you know?

The Eleutherococcus senticosus or “Siberian Ginseng” is commonly used in traditional Chinese medicine for its adaptogenic properties, helping the body to adapt to stress and combat states of weakness. The root, which is the medicinal part of the plant, is usually dried, ground into powder, and then processed and used as a substitute for Ginseng.