Oplopanax japonicus - (Nakai.)Nakai.
(Nakai.)Nakai.
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山添寛治
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下村愛子
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Curren Frasch
Description
Oplopanax japonicus is a deciduous Shrub growing to 3 m (9ft 10in). See above for USDA hardiness. It is hardy to UK zone 6 and is not frost tender. It is in flower in June. The species is hermaphrodite (has both male and female organs). Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It can grow in full shade (deep woodland) or semi-shade (light woodland). It prefers moist soil. The plant can tolerate maritime exposure.
Edible Uses
Young shoots - peeled and then cooked. Only the very young shoots are used. The roots can be chewed after peeling.
Medicinal Uses
Analgesic Antiphlogistic Antirheumatic Hypoglycaemic Tonic. The root bark and stems are analgesic, antiphlogistic, antirheumatic, hypoglycaemic and tonic.
Known Hazards
The plant is densely armed with spikes and these spikes are irritant. Although no specific mention has been seen for this plant, it belongs to a genus where the species are usually rich in calcium oxylate, this is toxic and if consumed makes the mouth and digestive tract feel as though hundreds of needles are being stuck into it. However, calcium oxylate is easily destroyed by thoroughly cooking or drying the plant.
Distribution
E. Asia - Japan.
Where It Grows
Coming Soon
Cultivation
Requires a cool moist soil. Prefers a position in light shade. Prefers dense shade and is probably best if grown in moist woodland. Tolerates maritime exposure. (Rather a strange report for a plant that needs to be grown in dense shade) A very hardy plant, tolerating temperatures down to at least -15°c, but the young shoots in spring can be damaged by late frosts. It is therefore best not grown in a frost pocket. This species used to be included in O. horridus as the Japanese form of that species, but it has recently (1991) been recognised as a distinct species. A very ornamental plant, but it is densely armed with spikes. It transplants easily and also tolerates pruning. The leaves and stems are excessively spiny.
Propagation
Seed - best sown in a cold frame as soon as it is ripe in the autumn. When they are large enough to handle, prick the seedlings out into individual pots and grow them on in the greenhouse for at least their first winter. Plant them out into their permanent positions in late spring or early summer, after the last expected frosts. Division of suckers in the dormant season. Root cuttings in a greenhouse in the winter.
