Growing Sansho: Year 3, Spring Update

My sansho (Japanese pepper, Zanthoxylum piperitum) is now in its third year, after its second winter…

This Is Sansho

By now, my research into the topic  has progressed to the point where I can tell that these plants really are sansho (rather than another kind of Zanthoxylum, especially the ones used for huajiao, i.e. Sichuan pepper).

I have grown them from seeds I got from Japan, admittedly, so they should be Zanthoxylum piperitum, the Japanese pepper, sansho.

You may think that this should be easy to tell, but botanical mis-classifications are still going around a lot; Sichuan pepper “corns” are still often traded as Z. piperitum. Except, as it turns out, they cannot be from that species.

Sansho (Japanese Pepper) leaves
And there, in the ideal case, sansho does have its characteristics, even in its leaf coloration

Species and Uses

On the other hand, kinome (young sansho shoots) and, perhaps to a lesser extent, sansho hana and sansho no mi (flowers and young “corns” of sansho, respectively), cannot be from a Sichuan pepper.

Sure, there are reports that Sichuan pepper leaves are sometimes eaten in China, as well, but the use of young sansho leaves and flowers and young fruit in Japan makes a lot more sense when seeing Z. piperitum.

Sansho is (often) ‘armored’, though

It just appears to grow rather less prickly, more delicately, when young. And its aroma is rather finer, too.

Growth and Winter Temperatures

For the first winter, I kept the sansho plants in pots and brought them into a cold (but not-freezing) place. I was told that the plants do not get frost where they (at least, the ones I got the seeds from) grow in Japan, so I wanted to be careful.

They got through that first winter quite alright; the main issue was that, by the time I was wondering if they did (when there was still frost outside), they already developed leaves again.

Last winter, I left the plants outside. Some of them are in a raised bed, others in a small greenhouse (in the ground of that), a few in pots I left in greenhouses. All of them had actually had issues during last year’s growing season; I was not there to take care of them, and they did not always get as much water as they should have. (Admittedly, that usually happens – and did happen – even when I was still around; I’m not much of a plant-waterer.)

The winter was very mild; the sansho plants again came back rather too soon.

Unsurprisingly, they came back sooner and quicker in the greenhouses than outdoors.

Frost Sensitivity

This spring has been yet another peculiar one, with temperatures rather too warm soon, followed by frost nights.

The two sansho outside in a raised bed got caught by that. One of them was already further along the new budding of the leaves, and all the buds froze in the frost.

The second plant, close by, was slower to come, but had developing leaf buds – and those also fell victim to the frost.

The sansho really seems to be sensitive – but then again, this frost after warm (to hot) days caused issues for other plants, as well.

Andaliman Pepper and Winter

This included the Andaliman pepper (Zanthoxylum acanthopodium) which is Southeast Asian, and keeps its leaves through the winter.

They just dry out a bit, then come back with the rising temperatures. Its fresh growth was also destroyed by the frost, though.

Andaliman Pepper frostbite
Andaliman Pepper frostbite

Re-Growth after Frost

All the plants came back with new buds taking over, though.

Sansho regrowth after frostbite
Sansho regrowth after frostbite

Incidentally, this also makes me more willing to “risk” taking off some kinome (young shoots) to try them in cooking; the sansho seems to be quite well-growing now that it’s better cared for and more established.


One of the young sansho plants also decided to flower already… which made it clear that that particular plant is a male, and that this sansho is dioecious.

That’s going to make things interesting. If I only had males, things wouldn’t work out for fruits and seeds.

Sansho flowers, male, in close-up

Next up, I am getting additional plants that a gardener in Germany has offered (of Z. piperitum, Z. schinifolium – Korean Pepper, and Z. americanum) – and of course, some attempts at germinating seeds from China are ongoing (but not looking good).

6 responses

  1. Any recommendations for soil/ph/nutrients and such? I’m having constant issues trying to grow here in North Alabama (Zone 7b), such as yellowing of leaves, blackening of trunk, etc, and no amount of nutrients seem to fix t.

  2. Gerald

    Oh boy, if only I knew – especially if you don’t just mean any Zanthoxylum but really sansho, Z. piperitum.

    At least where I am, nearly all Zanthoxylums, once established, grow like weeds. At least the 2-3 species I’ve had so far.

    The sansho, however, is the one exception. It’s fickle. It seems to like being in soil here much more than being in pots, with our usual (rather alkaline) soil that should be medium-rich in nutrients and drains water fast. In pots, with bought soil that’s a bit higher in pH and nutrients, I also often see yellowing – and I don’t know what is wrong, either.

    Doesn’t help that I have two plants right next to each other, of which the one has started growing really well while the other is a bit stunted. (And last year, both of those – the ones I show in the video at the beginning, iirc – suffered tremendously as they didn’t get watered enough and seemed to have had some other issue, as well…)

  3. Anonymous

    Hey – how did you grow them from seeds? I have a couple of plants from Japan as well – some of them didn’t make it through the winter but I have some seeds and I wanted to give it a shot to regrow them . Any tips & tricks / do’s and don’ts from your experience?

  4. Gerald

    This is going to sound as if I were trying to make fun of you… but it’s rather embarrassing to me, actually: I put the seeds in soil, they grew. Didn’t do anything special.

    I do have to say that they are tricky to grow. Other Sichuan pepper has proven much easier, but even that only applies for some species. The Japanese Z. piperitum seems really rather problematic!

  5. Hi I am interested in growing these as my wife from Japan really loves the aroma of the leaves and fruit. I wonder where to get some seeds? Thank you very much for your help.

  6. Aiken

    PH determines what nutrients are available readily, ie it can limit the uptake of iron which yellows leaves if the ph is too high.

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