Arctium lappa, burdock, is one of our most substantial wild foods. A native to the UK and Eurasia, burdock has long been a traditional vegetable and flavouring in Britain but is quite obscure now except for the vestigial burdock beer. In parts of Asia, however, the large starchy taproot, (known as Gobo in Japan) is still a popular and commonly cultivated vegetable.
I find much of it around farmed land, and since it is considered a rather dreaded weed, getting the landowner's permission (and we do need permission to uproot any wild plants) to harvest burdock root presents little problem. However, digging up a metre long taproot from packed waste ground or field margins is hard work. Luckily, the somewhat less substantial but even more delicious young, pre-bloom flower stalk requires neither digging nor permission. The only challenge is finding the perfect time when the shoot is still solid and the marrow tender, yet large enough (about 50-100cm long). I find this is just before the flower buds branch out and the central stem is already tall but still narrow and compact - usually around the middle of June in Edinburgh. I usually begin looking for these biennial plants at the end of May: in their second year, before they send up the flower shoot, the leaves make a rosette of huge leaves. Once the central stalk is tall enough, I cut it close to the ground and check that it is still solidly filled with marrow and not woody. I trim off all the leaves and the emerging flower buds (though all of these are edible too, they are quite bitter) and then peel the flower shoot twice: first, like a banana, to remove the outer peel, and then like a potato to remove the inner layer of stringy, tough and bitter skin. Wearing gloves for this is a good idea, since the skin will dye hands dark brown. The remaining marrow is about a centimetre or two thick and sixty centimetres long and has a delicate earthy flavour (very similar to the burdock root) with no trace of bitterness and a pleasant crunchy, juicy texture. It can be eaten raw, but is also good roasted, boiled, sauteed or pickled.
The peel is bitter, highly aromatic, and stains everything (including fingers) dark brown and is a favourite of mine to flavour beers and herbal bitters.
Arctium lappa is easily identified by the large, bushy second year growth, by the burrs still clinging to the tops of last year's desiccated brown stalks, and by the huge soft leaves. Besides butterbur/Petasites, Arctium lappa has by far the largest leaves in our landscape. To distinguish them from the tall, rounder, and singly stalked Petasites, look for Arctium lappa's large rosette of ovoid-arrow shaped velvety leaves emerging from the root and arranged around the base of the central flower stem.