How To Grow Traditional Japanese “Sansai” (Mountain Vegetables) In The UK. Many Can Be Grown In The UK’s Temperate Climate Though Some May Need Extra Attention.
Table of Contents
Sansai are the vegetables grown in the mountainous regions of Japan. Here are some that I have picked out and details of How To Grow Japanese Sansai Vegetables in UK. But before reading further please note that some Sansai vegetables come with a warning as either being regarded by Western cultures as being poisonous OR could be confused with some very toxic related plants. Read on only if you are prepared to do your own research on the veg listed. Being in the list doesn’t mean you should make any assumptions.
A Comprehensive List of Sansai (Potentially) for UK Gardens … How To Grow Japanese Sansai Vegetables
Sansai are wild or cultivated edible plants that are a cornerstone of Japanese Sansai cuisine. Many of these can be successfully grown in the UK with the right conditions. Here’s a list to get you started:
1. Fuki (Butterbur) Petasites japonicus
- UK Considerations: Can be invasive, so careful planting in a contained area is crucial. It grows wild where I live in Devon.
- How to Grow:
- Soil: Rich, moist soil in a shady, damp location (near a pond is ideal).
- Propagation: Divide established clumps in spring or autumn.
- Harvest: Harvest young shoots in early spring before they unfurl.
2. Wasabi Wasabia japonica
- UK Considerations: Requires cool, consistently moist conditions, which can be challenging in some parts of the UK.
- How to Grow:
- Soil: Rich, well-drained soil in a cool, shady, and constantly moist location.
- Propagation: Divide rhizomes in spring or autumn.
- Harvest: Harvest rhizomes after 2-3 years.
- I grow this in pots that sit in a large saucer of water. It is situated in piratical shade under some trees.
3. Mizuna Brassica rapa var. japonica

- UK Considerations: A hardy and adaptable leafy green.
- How to Grow:
- Soil: Well-drained soil in sun or partial shade.
- Propagation: Sow seeds directly in spring and autumn. Or, as I do, sow in modules for transplanting.
- Harvest: Cut and come again throughout the growing season.
- The image is of Mizuna in my unheated greenhouse in November. It was ready of its first harvest. Later it became very dense and yielded a lot of leaf from a small container. Today I tend to grow it as part of a polyculture of 5-7 different plants per container.
4. Komatsuna Brassica rapa subsp. nippo-oleifera
- UK Considerations: Similar to Mizuna in terms of cultivation.
- How to Grow:
- Soil: Well-drained soil in sun or partial shade.
- Propagation: Sow seeds directly in spring and autumn. Or again, as I do, sow in modules for transplanting
- Harvest: Cut and come again throughout the growing season.
5. Tatsoi Brassica rapa subsp. chinensis
- UK Considerations: Another versatile leafy green. Very easy to grow and seed fairly easy to buy.
- How to Grow:
- Soil: Well-drained soil in sun or partial shade.
- Propagation: Sow seeds directly in spring and autumn. Or again, as I do, sow in modules for transplanting
- Harvest: Cut and come again throughout the growing season.
6. Shiso Perilla frutescens

- UK Considerations: Can be an annual in cooler climates.
- How to Grow:
- Soil: Well-drained soil in full sun or partial shade.
- Propagation: Sow seeds directly in spring or start indoors for earlier harvests.
- Harvest: Harvest leaves as needed throughout the growing season.
- I like shiso as a tempura dish.
7. Udo (Giant Stinkhorn) Aralia cordata
- UK Considerations: May require a sheltered location.
- How to Grow:
- Soil: Rich, moist soil in a shady location.
- Propagation: Plant tubers in spring.
- Harvest: Harvest young shoots in early spring which maybe blanched.
8. Yamaimo (Japanese Yam) Dioscorea japonica
- UK Considerations: May not be suitable for all UK climates. Requires a long growing season.
- How to Grow:
- Soil: Well-drained soil in a warm, sheltered location.
- Propagation: Plant tubers in spring.
- Harvest: Harvest tubers in autumn.
9. Warabi (Bracken Fern) Pteridium aquilinum var. latiusculum
The Japanese eat this plant but most references in the West consider it poisonous and/or carcinogenic. So be aware of this before attempting to grow or eat this plant and take advice from elsewhere. I am only including it as it is listed in various Sansai texts and I want to draw attention to the issues and stop you rushing out and believing everything in text books without further research.
- UK Considerations: Bracken is highly toxic when raw. Requires careful preparation and cooking. Exercise extreme caution.
- How to Grow:
- Bracken is a widespread weed in the UK.
11. Seri (Japanese Water Dropwort) Oenanthe javanica
BEWARE .. do not confuse this with HEMLOCK WATER DROPWORT which is EXTREMELY TOXIC .
I have included Seri here to raise the issue of toxicity should you confuse the two species which have similar names. This could be easily done in some circumstances .. not all texts are clear on the difference. BEWARE
- UK Considerations: Requires a consistently wet environment.
- How to Grow:
- Soil: Plant in a pond or water garden.
12. Sansho (Japanese Pepper) Zanthoxylum piperitum
Similar to Szechuan Pepper.
- UK Considerations: Can be a small shrub or tree. Requires a sheltered location.
- How to Grow:
- Soil: Well-drained soil in a sunny location.
- Propagation: Can be grown from seed. Plant in spring.
- Harvest: Harvest leaves, flowers, and seeds for culinary use. The leaves can be eaten pickled, pan-fried, or deep-fried.
13. Mitsuba (Japanese Parsley) Cryptotaenia japonica
We are growing this in our Food Forest.
- UK Considerations: A hardy and adaptable herb.
- How to Grow:
- Soil: Moist, well-drained soil in partial shade.
- Propagation: Sow seeds directly in spring or start indoors.
- Harvest: Cut and come again throughout the growing season.
Important Notes: How To Grow Japanese Sansai Vegetables
- This is not an exhaustive list. Many other sansai can be grown in the UK with varying degrees of success.
- Always research and understand the specific requirements and potential challenges of each plant before cultivation.
- Consider the impact on local ecosystems and avoid harvesting from protected areas.
- Safety First: Some sansai require careful preparation and cooking to avoid toxicity. Always refer to reliable sources for safe preparation methods. If in doubt DON’T EAT.
This information is for guidance only. Always conduct thorough research and consider your specific climate and growing conditions before growing or eating these plants.
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