Over the last couple of years, growing Szechuan pepper has been increasingly popular here in the UK, although as the bushes take a few years to mature it’s unlikely many people have had much of a harvest.
Martin Crawford has a couple of mature specimens in his forest garden, and harvests up to 2 kg of seeds from each one – without attempting to harvest from the upper branches of these thorny shrubs.
There are several Zanthoxylum species that are suitable, and (according to Martin), they all have slightly different flavours. As with many edible plants from Asia, common names can be a minefield, with several species being referred to as Szechuan (or Sichuan) pepper, and more than one being commercially cultivated.
Martin refers to Z. alatum as the Nepal pepper; it’s also known as the winged prickly-ash. It grows to around 4 metres tall, appreciates a sunny spot, and is hardy down to -20°C.
Z. piperitum is the pepper tree or Japanese prickly ash. It grows 3-6 metres high. Young flowers, leaves and bark are all edible, although the seeds are the main harvest. It likes the same growing conditions.
Z. schinifolium is Szechuan pepper, and grows to around 2 metres. The leaves can be used as well as the seeds, and it can cope with light shade.
James Wong (and Wikipedia) refer to Z. simulans as Szechuan pepper, and Martin mentioned Z. sancho as being a smaller shrub with the same uses.
This beauty as the RISC roof garden is labelled as Zanthoxylum alatum planispinum, and is also known as the Toothache tree, as nibbling on leaves causes a numbing sensation.
Although referred to as ‘pepper’, and used as a spice, these species are in no way related to black pepper or chillies. They’re in the citrus family (the Rutaceae). The seeds themselves are tasteless; the spice is the papery red seed covering. You can dry the seeds and remove them to leave just the spice; or you can leave the seeds in, which is helpful if you want to use your pepper in a grinder. Commercial products often leaves the seeds in to make up the bulk.
Have you tried growing Szechuan pepper?