The Sichuan pepper tree is a shrub that bears the delicious Sichuan pepper.
Sichuan pepper facts
Name – Zanthoxylum species
Family – Rutaceae (Rue family)
Type – shrub
Use – standalone, garden box and flower bed
Height – 6 to 17 feet (2 to 5 m)
Exposure – full sun
Foliage – deciduous
Flowering – May to June
Harvest – September-October
Easy to grow, it does very well in our temperate climates.
Planting the Sichuan pepper tree
It is best to plant Sichuan pepper trees in spring or in fall.
If purchased in a pot or in a container, Sichuan pepper tree can also be planted anytime during the year while avoiding frost spells and de high temperatures.
Even though Zanthoxylum piperitum or Sichuan pepper tree is very tolerant as to the type of soil it is given, try to avoid waterlogged soil.
Right after planting, water abundantly and regularly without flooding the shrub’s roots, though.
- Adding fertilizer upon planting at the bottom of the hole helps increase rooting, regrowth and development of the Sichuan pepper tree.
- Follow our shrub planting guidelines.
Potted Sichuan pepper tree
This is a shrub that is perfectly suited to growing in pots or garden boxes, as long as you’re ready to repot it every 2 or 3 years.
- Double-check that the bottom of the pot has a hole in it.
- Place a bit of gravel or clay beads at the bottom to increase drainage.
- Fill in the pot or garden box with citrus-specific soil mix.
Propagating the Sichuan pepper tree
Best is to sow Sichuan pepper seeds in fall, when the pepper is harvested.
You can also start sowing your Sichuan pepper seeds in spring, after having kept the seeds in the cold for a while.
- Sample 6-inch (15 cm) cuttings from July to September, on semi-hardened wood (not yet hard).
- Remove lower pairs of leaves, keeping only one or two pair(s) at the tip.
- If possible, dip the base of the cuttings in powdered rooting hormones.
- Plant the cuttings in special cutting soil mix and keep cuttings near light, but not in direct sunlight.
- Keep the substrate a little moist and water less in winter.
- Protect your cuttings in winter, bringing them in a cool spot but keeping them out of the cold. Ideal temperatures range from 40°F to 50°F (5°C to 10°C).
- Read also: how to correctly prepare shrub cuttings
Caring for Sichuan pepper tree
This is a tree that doesn’t call for much care, but you can still increase its growth with a few good tips to favor a great Sichuan pepper harvest.
Considered hardy and resisting temperatures as low as 5°F (-15°C), it is a plant that readily makes do with the poorest soils.
However, it is important to water in case of high temperatures or prolonged dry spells, especially for pot-grown Sichuan pepper trees.
Diseases and pests occasionally found on Sichuan pepper
Usually Sichuan pepper resists diseases well. However, some diseases have been known to infect the plant:
- Pepper tree leaf blotch – Septoria pachyspora, a fungal disease that spots leaves.
- Fusarium wilt – leaves wilt away
- Alternaria – like Septoria, spots appear on leaves.
Not so vulnerable to parasites or pests, but sometimes invaded by aphids.
- Here is how to fight aphids off.
A video with special expert advice on caring for Sichuan pepper plants
Pruning the Sichuan pepper tree
Whether as a standalone, in a hedge or in a flower bed, it doesn’t really require any particular pruning.
But it is often nice to succeed in giving it a nice shape, especially when it is part of a hedge.
- Pruning is tolerated in spring or winter, as long as it doesn’t freeze of course.
- Never prune new growth, because that is what will bear the pepper.
- So best is to chop off any wood that grows towards the inside. This frees up the center part of the pepper tree and lets the sun penetrate deep inside.
- Remove weak or dead branches.
For potted Sichuan pepper trees, plan to have more drastic pruning to restrict its growth, and help it stay in the pot for a bit longer.
Harvesting Sichuan pepper
The harvest takes place at the end of the summer and at the beginning of fall, in general towards September-October.
That is when hard, little marbles appear, covered with a thin pink husk. This thin pink hull is the actual pepper we eat, not the seed-marble at all.
Place a tarpaulin or a bedsheet under the pepper tree and shake the trunk and branches to make the Sichuan pepper fall off.
Finally, dry the pepper before using it in cooking.
Unlike conventional pepper, the inside seed isn’t edible.
Sichuan pepper varieties
Sichuan pepper is a general term that includes several different species of the Zanthoxylum family.
- Zanthoxylum piperitum is the most common species, often sold in horticulture stores. Other names for this species include sansho and Japanese pepper, as well as Korean pepper. It is native to Japan and to parts of mainland China.
- Zanthoxylum simulans is also easy to find. Also called Chinese pepper. One of the tallest growing species, topping off at 20 feet (7 meters). Synonyms are Zanthoxylum bungei and Zanthoxylum bungeanum.
- Zanthoxylum armatum – Common name is green Sichuan pepper. Much harder to find for planting. Semi-wild Sichuan pepper variety grown in remote parts of Asia, among others in Bhutan. Also called wild peppercorn and Nepal pepper. Rarity and labor-intensive harvesting have increased costs. Distinctive taste.
- Zanthoxylum schinifolium – also named wild zanthoxylum or mastic-leaf prickly ash.
Other plants of the same genus don’t qualify as “Sichuan pepper” since they’re not specifically from Asia. But they’re very similar and share the same uses: spice, medicinal, and ornamental.
- Zanthoxylum americanum – native to North America, around the Great Lakes and the Mississippi watershed. Common name prickly-ash. It’s the type species for the Zanthoxylum genus.
Regulations concerning Sichuan pepper plant
We recommend checking with your local agriculture department before purchasing anything.
However, here are a few guidelines regarding the legality of growing and finding sichuan pepper plants. It’s only a clarification and should help you on your research and discussions with local authorities – we cannot be held liable for any mistakes or missed updates!
Importing Sichuan pepper in the United States
Until recently, a blanket ban on all citrus-related imports was enforced to protect US crops against citrus canker, Xanthomonas citri.
- from 1968 to 2005, the ban included all sichuan pepper materials (plants, seeds, and the spice itself).
- in the last three years of the complete ban, it was strongly enforced and tons of sichuan pepper spice were seized, worth millions of dollars.
- realizing that despite the massive contraband, citrus canker had not spread to US crops, the administration decided to alleviate the ban.
- from 2005 to 2007, importing sichuan pepper (the husks used for spice) was permitted, but only after a 140°F (60°C), 10 minute heat treatment.
- in 2007, the mandatory heat treatment was deemed no longer necessary, as long as the spice had been dried.
- Today, it seems possible to import dried sichuan pepper spice from your travels.
However, importing live plants and active seeds is not allowed.
- Currently, it isn’t authorized to import any plant materials of Zanthoxylum species at all, except for seeds.
- Seeds procured from certain countries must follow a specific heat and chemical treatment before being imported. This is because citrus canker has been discovered in those regions and it’s important to kill the bacteria off.
- Seeds from other countries are exempted, and may be imported and planted.
Heat treating for Sichuan pepper seeds meant for sowing
Here is the list of countries where a heat treatment is necessary:
- Asian countries – Afghanistan, Hong Kong, Kampuchea (Cambodia), Korea
- African countries – Ivory Coast, Mozambique, Oman, United Arab Emirates, Zaire
- and a set of island-nations – Andaman Islands, Caroline Islands, Fiji Islands, Home Island in Cocos (Keeling Islands), Rodrigues Island, Seychelles, Thursday Island
The treatment currently required for importing Sichuan pepper seeds from these countries is the “T203-p” protocol:
- clean seeds of any pulp, thoroughly
- Immerse the seed in water heated to 125 °F (51.6 °C) or more for ten minutes
- Then soak the seeds in a solution containing 200 parts per million sodium hypochlorite at a pH of 6.0 to 7.5 for two minutes at least.
This treatment must be performed in a facility approved by the relevant US government agencies before departure. You can’t do it on your own!
- It might seem like a drastic treatment, but it doesn’t harm the seed itself. Treatment times are short for that reason. The hull protects the plant seed and germination can still happen.
How to find sichuan pepper plants in the United States
Check with local horticulture stores. They deal with suppliers who know how to comply to regulations.
There are many online stores that sell plants and ship them through mail. It’s important to note that if they’re based abroad, the burden of complying to regulation rests upon you.
We recommend finding a US-based seller and grower. If you’re hoping to find a special Sichuan pepper variety, take it up with them. They will know if it’s possible to comply with the regulations. Hopefully they will be able to provide you with the pepper plant of your dreams!
Smart tip about Sichuan pepper
Take care to wear thick gloves for the harvest, because Sichuan pepper tree branches have spikes and thorns!
Credits for images shared to Nature & Garden (all edits by Gaspard Lorthiois):
Green sichuan pepper by szyj351 under Pixabay license
Red sichuan pepper by rduta under © CC BY 2.0
Sichuan pepper drying by Matthieu Lelievre under © CC BY-SA 2.0