Zanthoxylum armatum - Winged Prickly Ash

The Zanthoxylum armatum, known by its vernacular name Timut Pepper Tree, is a species closely related to Sichuan pepper, but with berries that are more lemony and aromatic, and stronger in flavour. It belongs to a group of tall shrubs and small trees called prickly ash trees, known for their aromatic fruits and foliage. Its colourful autumn foliage transitions from yellow-orange to purple. Relatively easy to grow, hardy below -15°C, this pepper tree with prickly branches is perfect for a defensive hedge. For this reason, it is best placed away from pathways and gloves should be worn during harvest.

The Zanthoxylum armatum is native to Asia and belongs to the Rutaceae family, like citrus trees. Its botanical synonyms include Zanthoxylum alatum var. planispinum, Zanthoxylum planispinum, Zanthoxylum alatum. It can be found in various habitats, below 3100 meters altitude, in Nepal and Tibet, China, as well as Bangladesh, Taiwan, Bhutan, India, Indonesia, Japan, Kashmir, Korea, Laos, Myanmar, Nepal, Pakistan, the Philippines, Thailand, and Vietnam.

The Zanthoxylum armatum has highly aromatic foliage with a lemon scent. This species sheds its foliage in winter and thrives in well-drained soil, even rocky limestone. This fast-growing small tree reaches 2 m by 1.5 m at 10 years and eventually reaches a height of around 4 m with a similar spread. Its graceful habit is naturally spreading, supported by a few main branches. Each bud on the branches is topped with 2 thorns. Over time, the thorns blunt, resembling small bumps. The branches bear opposite, lanceolate, ovate, or elliptical semi-evergreen leaves with essential oil glands and small prickles. When crushed, they release a fresh lemon scent. The leaves have prickles on the central veins. Flowering occurs in May-June, varying depending on the climate, on year-old branches. The flowers are small clusters or compound cymes of discreet yellowish-green flowers, at the axils of the leaves. This shrub bears both male and female flowers. After pollination, round fruits measuring 3 to 4 mm in diameter form on the female flowers. Their fleshy covering turns brown when ripe. These fruits are highly aromatic, with a fairly strong taste, citrusy aroma reminiscent of grapefruit, and possessing anaesthetic properties (similar to cloves). Indians reportedly chewed them to relieve dental pain. They are harvested from August to November.

Timut Pepper Tree grows in various soil types but prefers consistently moist soil in summer for a good harvest. It integrates well in an English-style or naturalistic garden. Left untrimmed, it naturally fits in an untamed hedge, alongside fruiting dogwoods (Cornus mas), rowans, viburnums, Amelanchier ovalis, Osage Orange trees, ornamental apple and cherry trees, bee bee trees, for instance. The spiny nature of its young branches makes this beautiful shrub an ideal candidate for a defensive hedge. In this use, it can be paired with Poncirus trifoliata, Pyracantha, jujube tree, hawthorn Crataegus monogyna, Japanese quince Cido, sea buckthorn, for example.