Zanthoxylum is the botanical genus to which Sichuan pepper, Japanese pepper, and various other kinds of such “peppers” belong.
Here, I want to give an overview of the species and the spices, linking to further entries that will go in-depth.
“Sichuan Pepper” – The Tree, the Species, or the Spice?
The basic issue is, as so often, that one can talk about these trees and the spice(s) they give in ways that are unclear.
“Sichuan pepper” could mean any kind of Zanthoxylum species (and thus, refer to the trees) and/or any kind of spice harvested from those.
There are some sub-categories that make things clearer, but confusion still reigns.
The botany of Zanthoxylum is rather badly understood in its link with the spices. Which species give which spice, to put it more simply, is not entirely clear (with exceptions).
This does not particularly help…
Zanthoxylum is known as Sichuan pepper (or following the old transliteration, Szechwan pepper).
Directly translating from the Chinese characters, some people also speak of flower pepper.
Sometimes, one also finds the old name of fagara.
In older (botanical) terms, Zanthoxylum is “prickly ash,” which one can sometimes even find on packages of the spice.
Sansho, the name of the Japanese pepper, should not be forgotten. (Strictly speaking, it should be transliterated as sanshou; the “o” is a long vowel.)
The Problem with the Word “Pepper”
As usual, the naming as “pepper” itself is already confusing.
It followed the usual pattern, where all spices with a spicy-pungent effect were named after the original, black pepper (Piper nigrum L.).
Speaking of Sichuan pepper, let alone peppercorns, also leads astray in another way.
What the Spice Sichuan Pepper Really Is
The problems continue, when it is said that Sichuan peppercorns were the seeds (or fruits) of Zanthoxylum.
Actually, the part used as spice are the pericarps (seed husks) that surround the seeds. During ripening and/or drying, those open to release the seeds.
Seeds and Quality
This is rather good to know, because the seeds are considered to be bitter. And they taste gritty, which isn’t a desired trait in food.
Whether bitter or not, one can recognize good quality (red) Sichuan pepper from the lack of seeds in it. During preparation of the spice for sale, they should have been removed. (Not to speak of bits of branches, thorns, and other woody parts.)
Zanthoxylum as “Herbs”
For Japan and its sansho, in particular, the use of other parts of the plants needs mentioning.
(In China, leaves are sometimes used, apparently, but this is less common or only a local use.)
This usage may well be connected with the difference in species and characteristics.
Botanical Name: Zanthoxylum spp.
Zanthoxylum belong to the Rutaceae, the Rue family. Citrus also belong to this family.
The genus includes some 250 species.
Zanthoxylum species can be found across much of Asia, North America, and, in fact, warm-temperate and subtropical areas around the world.
China (and the Himalayan region more generally), in particular, is home to a diversity of Zanthoxylum species.
In China, there are 41 species of Zanthoxylum. Of those, 25 are endemic, i.e. do not grow anywhere else.
At least two of those species are the most important sources of the spice Sichuan pepper. Or rather, the spices known as red and green Sichuan pepper?
Those two seeming varieties/types of Sichuan pepper actually appear to come from at least two different species. So, they are rather more different than commonly assumed.
Red Sichuan pepper, hong huajiao, is said to be from Z. bungeanum; green Sichuan pepper (also see below) is Z. armatum or Z. schinifolium.
In Japan, the most important species is Zanthoxylum piperitum (L.) DC., the source of the Japanese pepper, sansho.
This species also grows in Korea, but not in China (unlike previously assumed).
Korea also uses Zanthoxylum as a spice. Here, it is probably Z. piperitum, again.
Other species also seem to be used…
In the Himalayas, use of Sichuan pepper / Zanthoxylum in Bhutan and Nepal should be mentioned…
Bhutan is particularly interesting, given how it is a place rather like Sichuan, which used and still uses Zanthoxylum and came to love chilli peppers.
The Most Common Species in Asia
The most widespread species (in Asia), to switch to a botanical perspective, are Z. ailanthoides, Z. schinifolium, and Z. armatum.
Teng Jiao (?)
Zanthoxylum armatum grows in much of China, Bangladesh, Bhutan, India, Indonesia, Japan (including the Ryukyu Islands), Kashmir, Korea, Laos, Myanmar, Nepal, Pakistan, the Philippines, Thailand, Vietnam.
Chinese sources (though interestingly, not the Flora China) mention Z. armatum as the species that produces the green Sichuan pepper traded as teng jiao (“rattan pepper”)
Qing Huajiao, Green Sichuan Pepper?
Z. ailanthoides and Z. schinifolium can be found in China as well as Japan and Korea.
Z. schinifolium is the species that the Flora China labels as qing huajiao (and that is often given in discussions of qing huajiao, green Sichuan pepper).
Zanthoxylum acanthopodium should be mentioned for its newer occurrence in trade.
This species grows in Southwestern China, Bangladesh, Bhutan, India, Indonesia, Laos, Malaysia, Myanmar, Nepal, Thailand, Vietnam.
The appearance in Southeast Asia is rather important to note, because it is this species that produces Andaliman pepper, which has recently entered trade and was traditionally used by the local Batak people.
“Sichuan”Pepper in the USA
The USA actually also has Zanthoxylum species growing, Z. americanum and Z. clava-herculis.
They are known to grow in Texas and into the Midwest; there are traditions at least of their medicinal use, as “toothache plant.”
Diversity in Sichuan Pepper
Similar to the situation with black pepper, there is a diversity of Sichuan pepper(s); it is even less well known, though.
As mentioned above, wenn just talking of Sichuan pepper, nothing of the diversity is reflected.
Does It Matter That There Are Differences?
If you just want to talk about Sichuan pepper, the spice or the trees, in general, of course you could. Talking about native American Zanthoxylum species in their use as spice, it makes sense to address them as Sichuan pepper.
(Something like the homebrew name of “toothache plant” wouldn’t exactly have the same ring to it. “Prickly ash” is sometimes used even for real Sichuan pepper, could perhaps avoid some confusion, but takes it out of its most important cultural-culinary context.)
Differences between various of these “peppers” are great, however. “Sichuan pepper” as a spice in the trade can be anything from cheap and not-aromatic ones to the most numbing and intense.
That will matter, greatly.
Different species and different origins (growing regions, locations) produce different qualities, even within true Sichuan pepper.
Unfortunately, most of the time, all Sichuan pepper is just being traded as Sichuan pepper, without much of any indication of different kinds and origins.
At the very least, it is necessary to differentiate between green and red Sichuan pepper… and as already seen, there is (at least potentially) greater diversity already within these basic groupings.
Shortly, or following links in the text above already, I will continue with further entries on the different species and qualities, as I get around to writing about them…