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A FEW weeks ago, just outside London, I found a foodie jackpot: a patch of forest carpeted with wild garlic. The white flowers hadn’t yet emerged from their buds, so I might not have noticed the patch if I hadn’t been looking for it. When I last picked wild garlic in Cornwall a few years ago, the heady aroma from its blooms was so strong you could hardly miss it.

The plant usually called wild garlic in the UK, Allium ursinum (pictured above), can be found all over Europe and Asia in damp and shady woodland. It begins to grow in February, with flowers typically appearing in April, but the above-ground parts of the plant wither as summer arrives. You can eat all parts of the plant, though you should leave the roots so it can grow back next year.

Like other members of the Allium genus, wild garlic contains a high concentration of chemicals called cysteine sulphoxides. These are odourless and non-volatile compounds, but when the plant’s cells are damaged, enzymes convert them into secondary products called thiosulphinates. These include allicin, the molecule largely responsible for wild garlic’s pungent flavour. This chemical arsenal probably evolved as a defence against herbivory, but it is hopelessly maladaptive when it encounters garlic-loving humans.

If you plan to forage for any wild plants, do consult a proper identification guide and don’t eat anything unless you are sure you have identified it correctly – there are many poisonous plants that look similar to edible ones. A. ursinum can easily be confused with lily of the valley (Convallaria majalis), which contains cardiac glycosides like those found in foxgloves and cane toads.

Some other alliums are known as wild garlic in the US, including Allium triquetrum, which is called three-cornered leek in the UK. It is native to south-western Europe, but it is present as an invasive species in places including the UK, US and Australia. It can be found from autumn until spring.

Allium tricoccum, commonly known as ramps, is also popular with foragers in North America. Typically out from April to May, it looks like a spring onion with a red-tinted stem and a leafy top, and has a strong garlicky flavour.

My favourite way to eat wild garlic is to turn it into pesto, which you can also do with ramps. In her excellent book Salt, Fat, Acid, Heat, Samin Nosrat advises a light touch when using a food processor to make pesto, as the heat can cause the leaves to turn brown. To avoid this, roughly chop them by hand first, then pulse in the machine with olive oil and nuts, stopping frequently to push down any leaves that get stuck on the sides. When the mixture resembles a paste, tip it into a bowl and stir in some grated cheese, a pinch of salt, some lemon zest and a squeeze of lemon juice. Taste and add more salt and lemon if desired. Store it in jars with a layer of olive oil on top.

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