Rachel Lambert: forager, author, guide

All about Three Cornered Leek

I don't mind what you call it. In Cornwall and the Isles of Scilly this plant is often called wild garlic. Those who call it this know what they mean. They know they're talking about the onion grass, the long, thin one that smells of garlic. In Australia and New Zealand it's known as onion weed.

This blog is all about three-cornered leek, or whatever name you call it by. I describe its unique qualities, where it grows and how it compares to using wild garlic/ramsons (Allium ursinum) in recipes.

Three cornered leek is also in my Wild Food Foraging book and I regularly teach it on my foraging courses, especially in spring.

Three-cornered leek (Allium triquetrium) goes by many local names, but only one latin one. All the local names refer to its garlicky smell; onion grass, onion weed, wild garlic, three-cornered garlic, three-cornered onion or three-cornered leek. A member of the allium family it originates from the Mediterranean, Madeira, Canary Islands and North Africa.

It was originally introduced to the UK in the 18th century and the rest is history.

Why is it called three-cornered?

It has three-corners! A subtle triangle shape is visible when you horizontally cut a leaf and a clear triangular shape is visible on a cut flower stem. When not cut, a ridge is noticeable on the leaves, acting almost like a spine which makes the leaves more buoyant and upright.

Which parts can you eat?

You can eat all of this plant - the roots, flowers, flower buds, leaves and flower stems. Here in Cornwall I start eating it through winter when the leaves are greener and before the flowers start to show.

The Roots

Showing the roots of three-cornered leek

The roots of three-cornered leek are similar to spring onions though a little more watery and sweeter. Like leeks, they take a bit of time to clean up and remove the mud.

Remember that in the UK you need permission to dig up roots. However, I've never been refused permission to dig up these roots. People are often very grateful for me to take this plant away as it spreads really easily.

The Leaves

The leaves are the mildest part of the plant. Sometimes I cook them by sweating them down in a little oil or butter. They have a mild onion flavour this way.

The Flowers and Buds

The flowers and flower buds have a strong garlicky crunch. I love sprinkling them over salads and using them as an edible garnish. The buds are lovely pickled too. The flowers are white with a distinct green stripe on them.

Flower Stems

These are my favourite parts as they are the sweetest. I love chewing on them as I walk, they are one of my favourite spring walk snacks!

Wild Garlic

Three Cornered Leek v Wild Garlic

Wild garlic (Allium ursinum) is stronger, earthier garlic flavour. It has broad leaves and tends to grow in woodlands and near streams. It lends itself well to baking and cooking.

Three cornered leek (Allium triquetrium) is milder and sweeter in flavour. It likes to grow in warmer climates and thrives well in open spaces and hedgerows in Cornwall and the Isles of Scilly. It lends itself well to using raw, like spring onion.

19 comments on “All about Three Cornered Leek”

  1. Hi, Im' working on rewilding (turn into meadows) road verges in my parish in south Devon. I found your website when I was looking for information, to pass on to the general public, on how to destigush between wild garlic/Ramson as in the nativ species(Allium ursinum) and the non native, very invasive Three-cornered garlic (Allium triquetrum).
    Can you please help spread information on the threat to our native plants non native species, like three cornered garlic, impose. As much as possible need so be done to eradicate them (not into someone's compost though)
    Many thanks,
    Maria Christell
    from Plantlife’s Road Verge Guide (p.7)

    Three-cornered garlic (Allium triquetrum). This highly invasive non-native bulb produces white flowers in spring and was introduced into Britain from the Mediterranean, first escaping from gardens in 1849. It’s spreading rapidly along road verges and is now found from Land’s End to Orkney, being especially abundant in south-west England, south-east England and around the Welsh coast. Like other invasive arrivals such as montbretia (C. x crocosmiiflora) and hybrid bluebell (Hyacinthoides x massartiana), it forms dense colonies that can out-compete our native flora.


    1. Hi Maria, thanks for getting in touch. As you'll know my working is about teaching people about plants and their uses, including eating them. This can be especially useful to reframe so-called invasives and see (and use) their positive qualities. I hope you find my site useful to help people use and befriend (by eating) this plant too. BTW, my understanding of re-wilding is letting nature take its course, I'm not a fan of naming certain plants as bad or wrong. This is also an amazing spring medicine, afterall! Furthermore, may be I (and many of my fellow humans) are also an invasive, as our human population is huge now and threatening many species, and I'm not completely from the British Isles (I have mixed heritage). So I feel how we talk about so-called 'invasives' and treat them, see them, use them is important too. All the best, enjoy nature!

  2. Well done Rachel! Like you, I find this arrogant attitude of calling such a a brilliant tasty beautiful plant absurd!
    We as you say, are the invasive species!
    Rewilding means what it says without the prissy labeling of good or bad!
    I have a wild 3 acres and leave the ragwort for the cinibar moths!
    The tussock grass for the voles and try to help nature survive despite the immense juggernaut of development in our beautiful Cornwall!

  3. Re:rewilding. I have been rewilding my garden for the last 30 years, it started slow but it gained momentum and I really love it now.In my opinion, you can't police a rewilding project: the plants will only grow where they want to grow, and nothing can be forced. I am glad to say some plants that are known rarities now are happily thriving in my garden, because I let them do their thing. Personally I love Three Cornered Leek. I am on a low gluten, low FODMAP diet because of IBS, and this plant gives me that essential little garlic kick to the safe soup I am coincidentally cooking as I write.
    As an urban gardener I have a regular disagreement with the Council who recently butchered my beautiful wildlife hedgerow without warning, in the middle of winter when the birds and beasts needed the food, shelter and nesting materials.One thing I know,tidiness is the enemy of wildlife.We have to stop the tendency to control,provide the right conditions, and let Nature do her thing. Nice website!

  4. I'm in Australia and have 3 cornered leek everywhere. We call it onion weed and everyone hates it. I discovered it's edibility a few yrs ago and am trying to educate people of its uses. I no longer have a weed but a crop.

  5. Hi Rachael,
    Just moved to the Isle of Wight and found your site when finding out about the garlic tasting clumps of grass, I now know to be Onion Grass, in my new garden. We have the broad leaf type too, under the trees so it’s all good for Alliums around here.

  6. Hi, I’m sorry but we should be able to differentiate between species that are invasive and those that aren’t not. This plant takes over gardens and verges and is truly destructive of any other species, so it’s best to control it. It’s not a matter of ideology , just simple about protecting the countryside. Dig it up and eat it for sure !

    1. Thanks for your opinion, plants spread when the space is available. Humans, in my opinion, are far more invasive and destructive than this fantastic edible!

  7. Hi, my garden is full of Allium Triquetrum. Can anyone tell me if there are any benefits to having them in a vegetable garden such as attracting any beneficial insects? They are very invasive and spread very vigorously.

  8. I live on the Irish Sea coast in County Down. Three cornered allium is very common on roadsides around Bangor. It also grows on the edges of playing fields and so on, where the local council is rewilding. I logged onto this site because I wanted to know if it is edible, because I have an abundant crop on my doorstep. It flowers throughout the winter and dies away during the summer. On my walk today I noticed that the leaves are green and luscious, and some are in flower already - so it doesn't seem to mind the Northern climate. Today is 30th November 2023.

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