Plants that make your mouth fizz, tingle and go numb

This week I look at the numbing ability of Szechuan peppers, chillis and those crazy electrifying flowers known as buzz buttons or electric daisies

It’s the time of year when my Szechuan peppers are looking wonderfully autumnal and the fruits are ready to harvest. If you don’t know, Szechuan peppers have this ability to make your mouth numb. Somebody asked me the other day about the science behind this effect, and that got me researching and thinking about other edible plants that also have a tingling effect in the mouth.

We have two particular types of receptors on our tongue, TRPV1 receptors that are responsible for detecting heat and pain, and the TRPA1 receptors that detect chemical irritants. It is these two receptors that are involved with the numbing and tingling effects.

Szechuan peppers

Szechuan peppercorns release a compound called hydroxy-alpha-sanshool, which binds to these receptors, causing a sensory reaction that produces a numbing and tingling sensation. This is described as má in Chinese, one of the two key taste elements in Szechuan cuisine, alongside the spiciness of chilli peppers (là). The tingling effect is temporary but can be quite intense, and it's part of what creates that unique balance of numbing, spicy, and aromatic tastes.

You can use these peppercorns in different ways. The starting point for me is to toast and grind the peppercorns. I heat them in a dry pan for a few minutes so they start to release their aroma and then grind them in a pestle and mortar. And then you could:

• Make a classic Chinese Five Spice, mixing the ground peppercorns with star anise, clover, cinnamon and fennel.

• Added to a sauce or marinade for some zing.

• Make a dipping sauce of soy sauce, rice vinegar, a touch of garlic, a pinch of ground Szechuan pepper and a little sesame oil.

• Mix with coarse seasalt to create a meat rub or a bacon cure. [One of the tutors of our butchery courses here in the farm used Five Spice as the basis of his dry cures and made some great tasting bacon.]

• And my favourite  - add whole peppercorns to a pickled gherkins to get a numbing kick which can take guests by surprise.

I am sure there are many other ways to use this unique pepper so please add to my suggestions.

Different species of Szechuan pepper

When I first started growing Szechuan peppers around 12 years ago, there wasn’t much choice of species other than Zanthoxylum simulans, but now you can find a wide range of species. Most tend to be easy to grow, coping with sun and shade, tolerant of a wide range of soils, very hardy and drought tolerant which is a useful climate-forward feature. One of my Zanthoxylum simulans is growing well in very poor, rubble-based soil. But beware, these are thorny shrubs, many bearing evil spines several centimetres long which can make harvest quite painful. But they do make useful livestock barriers!

The fruits are ready to pick in late autumn. Once harvested, they are spread out to dry, something that takes a couple of days. As they dry, they open and release the black seed which doesn’t have much flavour. My peppercorns have a punchy lemon flavour and intense spicy aroma.

Chinese pepper tree in autumn

Chinese pepper tree or Chinese prickly ash   (Zanthoxylum simulans) 

This species is widely available. It’s easy to grow, and it can reach the size of a large shrub in a few years and bears pink fruits.

Japanese Sancho pepper (Zanthxylum piperitum)

I have never grown this species, but many have recommended it.  Its another thorny, medium sized shrub with red fruits. The red peppercorns have a citrus flavour and a great aroma. Traditionally, they are used in the blended spice, shichi-mi or Japanese 7 spice which comprises poppy seed, sesame seed, ground ginger, red chilli pepper, and Yuzu peel alongside the Sancho peppers. Also, the edible  leaves can be used to make a pesto.  Pennard Seeds are selling a compact variety’ Devon’ which was found growing in the county.

Northern prickly ash or Toothache tree (Zantoxylum americanum) Native to central and eastern USA, this pepper has huge thorns and bears red fruits

Korean lime pepper (Zanthoxylum coreanum)   This species is so named as the crushed leaves have an aroma of limes

Shiny leaf prickly ash (Z. nitidum) has a scrambling habit and can be encouraged to climb.  

My go-to nurseries for Szechuan peppers are  Pennard Plants where you will find a wide range of species in stock, from saplings to large specimens and expert advice. Mark Diacona has lots of experience growing these plants and you can buy them via Otter Farm

Chillis

Chilli peppers make your mouth feel hot or spicy because of a compound called capsaicin that binds to the TRPV1 receptors. Then your brain interprets the sensation as pain or heat, even though there's no actual temperature change. In response, your body tries to cool you down by producing saliva and sweat, and this process can sometimes make you feel flushed. But after a while, the sensation fades as your body adapts to the ‘burn.’

So, basically capsaicin tricks your brain into feeling like you're experiencing a burn, which is why some people love the heat and others can’t handle it!

I am not going to delve into growing chillis as much is written elsewhere but I did cover chillis in my post about Seaspring Seeds and Joy and Michael have a brilliant seed list and can offer plenty of advice.

Buzz button or Electric daisy (Acmella oleracea)

Chewing this flower has been likened to licking a 9v battery - OK, that’s not something I can remember doing, but you get the idea. You get a buzzing or tingling sensation in the mouth that lasts a few minutes, hence the name buzz buttons.

This time the active ingredient is spilanthoiI, which interacts with the TRPV1 and TRPA1 receptors and the result is this tingling and numbing effect. The numbing triggers salivation, and interestingly, some people report that their taste buds become more sensitive and this can enhance the taste of other foods. 

The leaves are edible too and can be added to salads to give a mild tingling or effervescent effect and they are said to enhance the taste of the other salad leaves. Has anybody tried this? You can read an interesting blog on Aerogarden.com about electric daisies and some of their culinary experiments.

Medically, sucking on the ball-shaped flowers can help with toothache, hence its alternative name the toothache plant. It is also said to have anti-inflammatory and antibacterial properties.

I mentioned these plants in a post a few weeks ago when I was describing my visit to Hyde Hall’s World Garden. Its a trailing plant with conical ball-shaped yellow flowers with red centres. The plant is native to Brazil but its now found growing across the tropics. It grows well in a warm climate (USDA 9-11) but can be grown as a half hardy annual in cooler zones. It’s a fast growing plant that likes a sunny position with well drained soil, but it can also be grown in a container, and is quite demanding of water and feed. 

I am definitely going to grow some electric daisies next year so 'I’ve been looking for seeds. One of the more reliable outlets is Chiltern Seeds.

If you have grown these plants or cooked with them I’d love to hear from you in comments.

Happy Gardening

Sally

PS If you enjoyed reading this post, please click the like button at the bottom, it really helps make my posts more visible on the app. Thank you

Talks

I am talking at a number of venues in the coming weeks. Most of these clubs allow non members to attend for a fee.

19 November Mayfield Horticultural Society by zoom

21 November University of Bristol Botanic Gardens

23 November I am talking at the inaugural LandAlive conference at the Bath and West showground on Sat 23 November. The topic is on creating a climate resilient allotment.

4 December Castle Cary Gardening Club