Invasive plants evoke heated feelings. Certain plants, whether we appreciate it or not, are evolutionarily disposed to the rapid colonising 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 these plants are edible, require little or no cultivation, and are really tasty, then they are well worth considering for your permaculture plot, where they offer a number of yields.
The three-corner leek - Allium triquetrum (Liliaceae) - 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, it has 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. 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 new growth rising from small, white bulbs, which are often at or just below the surface of the soil.
How to identify three-corner leek
Each bulb produces four or five 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.
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 45cm, eventually producing a drooping, delicate, bell-shaped inflorescence.
The white sepals and petals have thin green vertical stripes, making these flowers easily identifiable from otherwise similar-looking white bluebell cultivars, summer snowflake and others.
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, finishing black.
Foragers might say that they can know an Allium from its smell. Fair enough if you have picked leaves only from an identified single clump. But 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 merge 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.
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 three-corner leeks
All Alliums and all their parts are edible. Three-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.
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 three-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 anti-microbial, anti-fungal, anti-viral, and antiseptic, so this plant will likely show some activity in these areas.
This delicious plant is one of 52 wild food species featured in my new foragers playing cards. All the plants included are temperate zone species, so these cards can also be used in Ireland, North West Europe, North America and parts of Asia! All photos are my own work. Email email@example.com if you would like a deck!