Thuja orientalis Seeds | Oriental Arborvitae
LATIN NAME: Thuja orientalis
COMMON NAME: Oriental Arborvitae
Plant Profile
Thuja orientalis, now usually placed in the genus Platycladus, is the small conifer of Chinese temple courtyards and of Mediterranean hedges. It grows as a dense, conical tree to ten metres, with flattened sprays of scale-like leaves held vertically rather than horizontally, which gives the foliage a distinct look. The bark is reddish-brown and peels in strips.
The species is native to the hills of northern and central China and to Korea, and it has been planted for so long that wild populations are hard to identify. It is one of the most common trees of Chinese cemeteries and temple grounds, and it is grown throughout the temperate world as a hedge and as a specimen.
Science & Biotechnology
The foliage contains an essential oil rich in thujone, together with pinene and cedrol, and the oil is toxic in quantity: thujone is the compound that gives wormwood its reputation and that causes seizures at high doses. The oil is used externally and as an insect repellent, and it should not be taken internally.
The seed, called bai zi ren, is used in Chinese medicine as a sedative and as a treatment for insomnia, and it contains fatty acids and a small amount of essential oil. The tree is also one of the parents of many garden cultivars, selected for colour and for a compact habit, and the juvenile foliage is often golden or blue-green.
Uses & Benefits
The tree is grown as a hedge, as a specimen and as a container plant, and it is used in cemetery and temple plantings across East Asia. The wood is fragrant, light and durable, and it is used for furniture, for boxes and for carving.
In Chinese medicine the seed is used for insomnia and for palpitations, and the twig is used for coughs and for bleeding. The leaf is used as a wash for skin complaints, and the oil is used as a rub for rheumatism. The plant is not a food, and the oil should not be ingested. The wood is also burned as incense in Chinese temples, where the scent is considered purifying.
Growing from Seed
No pretreatment is needed, but the seed is in no hurry. Sow at 18 to 20 degrees in spring, and seedlings appear in three to six weeks. Named forms are propagated by cuttings in late summer, since seed does not come true.
The tree wants full sun and a well-drained soil, and it tolerates drought, pollution and hard pruning. It is hardy to about minus twenty. Shear hedges in late summer, not in spring, and avoid cutting into old, bare wood, since the plant does not resprout from it. It is prone to root rot in wet ground. It also makes a good container plant for a terrace.
Our Take
A workhorse conifer for hedges and temple yards, with a fragrant wood and a seed that is a medicine rather than a food.
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