Zanthoxylum simulans

The Zanthoxylum simulans, sometimes called the Ash-leaved prickly ash, is part of a group of small Asian trees known for their aromatic fruit used in cooking as Sichuan pepper. This species simulans is particularly interesting to kitchen gardeners for its ease of cultivation, hardiness, peculiar warty bark, and vigour. Its inconspicuous spring flowering is followed by small pink-red berries, whose dried and ground pink peel is used as a spice. The combination of the pink fruits and the foliage that takes on coppery golden tones in autumn is stunning. It is perfect for a free hedge, and its young, thorny branches are ideal as a defensive hedge. For this reason, it is best to place it far from a pathway and wear gloves for harvesting!

Native to China and Japan, the Zanthoxylum simulans belongs to the same family as citrus trees, the Rutaceae, which shares very aromatic foliage. It loses its leaves in the winter, tolerates temperatures down to -18°C (1°F), and grows in any well-draining and sufficiently deep soil. Late frosts can, however, harm its flowering and burn its young shoots. The Chinese pepper tree can only be stopped by thick shade.

This small tree, which grows rapidly in cool and fertile soil, averages 4m (13ft) in height with a similar spread at maturity. It has a graceful, naturally spreading habit, supported by flexible branches. The trunk and branches are adorned with slender thorns that widen significantly over the years while their tips remain blunt. They eventually form curious growths resembling large warts. The branches bear deciduous leaves arranged alternately, ranging from 10 to 20 cm (4 to 8in) long, divided into 3 to 11 shiny leaflets, serrated along the edges, and produce essential oils and small prickles. When crushed, they release a scent that is spicy, woody, lemony, and slightly peppery but mild. They are a beautiful dark green, turning yellow-orange in autumn before falling. Flowering already occurs on plants aged 3 or 4 years. It takes place in May-June, depending on the climate, on one-year-old branches. It consists of small clusters or cymes measuring 3 to 5 cm (1 to 2in) in diameter, composed of small cup-shaped flowers in yellow-green. Male and female flowers are found on this shrub. After pollination, round fruits form on the female flowers, measuring 3 to 5 mm (1in) in diameter, spherical and warty. The fruit is pink-red when ripe, opening to reveal black and shiny seeds. Only the peel is consumed once dried and ground. Note that the ash-leaved prickly ash tolerates pruning very well, even severe pruning.

In the kitchen:

The Sichuan pepper has pink berries, different from the "pink berries" or "pink pepper" sold in the spice section. The latter comes from the Brazilian pepper tree, which is native to South America. The pink "skin" of the fruit of the Sichuan pepper is used to enhance preserves, rice, salads, and cooked dishes in Asian cuisine. The dried leaves are also used, especially in Japan, and have a similar aroma to the berries.

In the garden:

If you have an English or naturalistic garden, you can add charm by planting a small tree with fascinating bark. When planted alone, it can become a stunning specimen that will impress your visitors. You can trim the lower branches up to 1 m (3ft) from the ground to expose its trunk or leave it untrimmed to fit in an untrimmed hedge. It can be planted alongside dogwoods, rowans, viburnums, Osage orange, ornamental apple and cherry trees, and honey locusts. Its thorny young branches make it an ideal candidate for a defensive hedge. You can plant it with Poncirus trifoliata, Rosa moyesii, Pyracantha, hawthorn Crataegus monogyna, Japanese quince Chaenomeles, and sea buckthorn.