Three corner leek. From pest to pesto

Three corner leek pesto – A quick and tasty recipe from a highly invasive non native plant.

Three corner leek (Allium triquetrum)  Liliaceae

Invasive plants evoke heated feelings. Certain plants, whether we appreciate it or not, are evolutionarily disposed to the rapid colonisation of land, especially bare soils. When wandering the British countryside, you will notice that some of the flora found here can be aggressive colonisers of ground.

So if the plant is edible and tasty, its a no-brainer right? Surely we eat em to beat em?!

The 3-corner leek is native to the Mediterranean area. First introduced to cultivation here in 1759, it was found well established in the wild less than a century later. With a late autumn to spring growth cycle, the plant found a profitable niche here, and when coupled with a handy seed disposal relationship with ants, it gives the plant an advantage when establishing in new sites.

The plant will be found in a number of lowland settings in the UK, particularly loving life in our moist South West counties such as Devon and Cornwall, and commonly appears throughout Southern England except around Salisbury Plain.

Scattered populations are increasingly recorded in town and country throughout the UK.

The abundant winter foliage and copious spring flowers are increasingly found in urban areas

Large dense carpets of this bulbous perennial are not uncommon. With salt-tolerance, it also enjoys various coastal settings up and down the isles.

It re-appears when most of our herbaceous plants are either dormant or overwintering. Keep an eye out in October and you will see quite a bit of new growth rising from their small white bulbs, which are often right at the surface of the soil.

How to identify three corner leek

Each bulb typically produces 4 or 5 strongly keeled, glossy-green leaves with parallel veins, entire margins, and leaf tips that are often acutely pointed. When looking underneath, the mid-vein is prominently ridged.

Toward the base, its hairless leaves are distinctly triangular in structure. If chancing upon a large stand of the plants, you will find the foliage tends to drift in the same direction, creating a pleasing long-grass sward effect.

3 corner leek is invasive and will make dense swards
3 corner leek spreads rapidly and can quickly take on the appearance of a lushious dense grass sward.

If you crush a leaf, the unmistakeable, sulphurous Allium chemistry will quickly be detected. You might well find that the strength and quality of the aromatics differ dependent on soils and temperature…at least the strongest and most pungent stuff I have foraged, came on cold January days from acid soil in Devon and on Barnes common, SW London.

Flowering occurs during April and May, like a number of our native ephemeral Allium species. The distinctive triangular flower stem will grow to around 45 cm, eventually producing a drooping, delicate, bell-shaped inflorescence. 

The white sepals and petals have thin green vertical stripes, making these flowers easily identifiable from similar-looking plants white bluebell cultivars (Hyancinthoides non scripta ‘Alba’), or the summer snowflake ( Leucojum aestivum) .

The green striped corolla of three corner leek

The corolla displays typical lily family patterns of three stamens and a fused, three-lobed stigma can be seen. Seeds are similarly produced in groups of threes, initially green coloured, then finishing black.

This larger than life shot shows the remains of the petals surrounding the seed pod. Young green seed pods are similar in size to petit pois peas
Dried seed pods eventually open to reveal three black seeds
Summer snowflake appears with blunter leaf tips and without the pronounced keel undersides. The corolla is tighter, without stripes, and with a yellow center

Foragers might say that they can know an Allium from its smell. You cannot rely on this diagnostic characteristic when harvesting large amounts.

The nature of essential oils means we inevitably transfer them onto our fingers, so how do we know that we are not accidentally picking poisonous daffodils, snowdrops, or crocus, growing amongst them?

You need to know the leaf structure, the colour, the texture, and other aesthetic and mechanic qualities that can only come from engaging with the plant.

With very similar-looking plants, close study of numerous features becomes vital, especially when the plant is young. Our brains can quickly file this range of information presented to them, merging it with observations about the landscape, soil, habitat, micro-climate, and time of year; while observing the habit of the plant itself.

So, knowing the blue green colour and blunt-tips of daffodil leaves, and the length and width of crocus or snowdrop leaves compared to this particular garlic relative, helps to ensure that even on auto-pilot, and working at speed, the key check points are covered when harvesting.

I work with the premise that I also get two further opportunities to check the leaves; firstly during preparation of the plant, and finally, on the chopping board, or as I add to the pot.

Using 3 corner leeks

All Alliums and all their parts are edible. 3-corner leek, with its luscious leaves tender stems and crunchy flower buds and bulbs, is particularly versatile. If you can eat all parts of the plant, it’s in season all year – what more could you want!? With a strong onion-leek flavour, this plant can be added to many dishes.

Three corner leek pesto, with soaked sunflower seeds, 2 cloves bulb garlic, olive oil, lemon juice, basil, salt, pepper. Photo: Tobias Snow. View more on Instagram.

I harvest leaves throughout winter, from November onwards; to add to sauces, salads, pies, pesto and soups, then harvest the first of the sweet, pungent flower buds for lacto-fermentation in March. 

Bunches of pre-flowering stem ‘leeks’ can also be harvested in late March and April, before the flowers eventually open. These can be used in salads or as garnish. The young, green, and crunchy seeds can be eaten raw, fermented, or dried.

From late May onwards, as the plant enters its dormancy, I harvest the small marble-sized bulbs for preserving. Juicy and crunchy, these are quite fiddly and time consuming to prepare, but are simply stunning when lacto-fermented for a couple of weeks!

Medicinally, we could potentially use 3 corner leek like a milder version of garlic, but I always reach for bulb garlic out of instinct – often carrying a clove – so don’t employ the other species for medicine. The Allium essential oils are known to be antimicrobial, anti-fungal, anti-viral, and antiseptic, so this plant will likely show some activity in these areas.

This delicious plant is one of the featured species in my foragers playing cards, and the ‘top trumps’ style card game. You can find these in the foraging resources shop. 

Happy foraging!

 

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