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Growing Zanthoxylum
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Zanthoxylum - Growing Guide

Growing Zanthoxylum

While one could very easily be put off growing these trees because of their huge, flattened, chubby, rose-like spines we have persevered here at Caerhays to produce some fine small trees which, after 20 years of growth in full sun in the open, now have attractive foliage and a huge crop of pepper fruits for which we have managed to find a small commercial market. The trees have developed a mounded, spreading, dome like shape and we would recommend Zanthoxylum piperitum (Japan pepper) and Zanthoxylum simulans which we believe will grow in popularity and in garden use.

Interestingly the last two decades have seen the arrival of new species of Zanthoxylum from China and North Vietnam which have equally horrid spines but may yet have other attributes in the garden.

Burncoose Nurseries offers Zanthoxylum piperitum in an attractive purple leaved form from China and Japan. It is a deciduous shrub, becoming a small tree, with pinnate glossy leaves of up to 6in in length. Each leaf has 11 to 23 ovate toothed leaflets which turn yellow in autumn. In June this plant produces panicles of small cup shaped yellowish-green flowers. These are followed by reddish fruits which turn into black seeds which hold on the bush or small tree. They are used in medicine and as a peppery condiment in some Japanese dishes.

Zanthoxylum piperitum

Also available is Zanthoxylum simulans which is a larger spreading tree with pendant branches. Ours is now 10-12ft tall with a spread of nearly double this. Glossy dark green pinnate leaves each with 11 ovate leaflets. The autumn colour is impressive with us which begins yellow and then turns reddish yellow. The fruits are ¼in across, warty red and then splitting to reveal glossy black seeds. This species is a native of China and totally hardy. When it is plastered in fruits in September and October you can readily forgive this plant its spines until to begin to try to pick them! Thick gloves are essential.

Zanthoxylum simulans

These trees can be grown from root suckers removed from near the base of the plant over winter during dormancy. Seeds should be sown in a cold frame in the autumn. Semi ripe cuttings in midsummer are possible but, with so much fruit, why bother