Arctium lappa Seeds | Greater Burdock
LATIN NAME: Arctium lappa
COMMON NAME: Greater Burdock, Gobo
Plant Profile
The burr is not a fruit in the everyday sense but a whole head of fruits wrapped in an involucre. Its outer scales, the phyllaries, end in stiff hooks that bend rather than break, so a passing animal picks up the head and carries it away.
Three burdocks are common in Europe. A. minus has the smaller heads and hollow leaf stalks, A. tomentosum carries a cobwebby felt over the underside of the leaves, and A. lappa has the biggest heads and solid stalks. The petiole character is the one to check, since head size varies with the season.
In the first year the plant makes no flower at all. It builds a rosette of broad heart-shaped leaves, softly felted underneath, on stalks long enough to arch, and drives a long fleshy taproot downward. That root is the crop.
The root stores its carbohydrate as inulin, a chain of fructose units rather than the starch found in most vegetables, and inulin makes up a large share of the dry weight of a good root. The same tissue holds bitter lignans, chiefly arctiin with its aglycone arctigenin, which is where the medicinal interest begins.
Lift roots at the end of the first season for the kitchen, or leave them for a heavier crop and accept a coarser texture. Any root left in place will flower in its second year, and if you want seed, take it from one plant only. Lift with a fork, cut the leaves, and store roots in damp sand in a cool shed until they are needed.
The pests are modest. Caterpillars of moths have been recorded on the foliage and aphids cluster on the flower stems in dry summers, but neither threatens the root, so the practical answer is simply to keep the bed weeded and the plants thinned.
Science & Biotechnology
Arctiin is a glucoside that releases arctigenin when the sugar is removed, and arctigenin has been studied for anti-inflammatory and antiviral activity in laboratory systems. It is one of the few weed-derived lignans to have crossed into serious pharmacological work, and the work is ongoing rather than settled.
Uses & Benefits
Because inulin behaves as a soluble fibre that gut bacteria ferment rather than as a sugar the body absorbs, burdock root has been looked at as a source of fructan for food use as well as a vegetable. Roots are washed, sliced and dried for that trade, and roasted slices make the dark, bitter base of the old British soft drink.
Dig with a fork well clear of the crown, lift the root in one movement, and you will lose fewer to snapping. For the kitchen the skin is scraped rather than peeled, because most of the flavour and the aroma sit just under it.
The vegetable trade and the weed are the same plant. What makes the difference is soil preparation and timing, not variety, although named lines such as the long Japanese gobo types have been selected for straight roots.
Scrape the root clean and shave it into thin diagonal slices, then stand the slices in water with a little vinegar so they keep their pale colour. The classic Japanese treatment is kinpira, sliced root braised with carrot, soy and a touch of chilli, which softens the bitterness without hiding the earthiness.
Before carbonated colas arrived, a drink of burdock root, dandelion root and a little sugar was sold on British street corners and in pubs. The recipe still turns up in old cookery books, and the roasted roots are now sold as a coffee substitute of the same bitter family. Left to flower, burdock feeds bees on its purple heads and goldfinches on the seed that follows, which is why it belongs at the rough end of a wildlife garden.
Growing from Seed
Burdock is a biennial grown from seed sown where it will stand, because the taproot cannot be moved without forking. Work the ground deeply and remove stones, since the root grows straight down and will divide around any obstruction it meets.
Sow the seed less than a centimetre deep in rows about 45 cm apart, and thin the seedlings to roughly 15 cm within the row for roots you can lift whole. Keep the ground watered through the first summer, and the roots will be long by the time the leaves begin to die down.
Our Take
Burdock is worth growing even if you never eat it, because the burr is the best botany lesson in the garden. The Japanese vegetable line is available as Gobo Takinogawa Long, and if you want to compare the smaller wild relatives the lesser burdock, Arctium minus, and the felted woolly burdock both grow from the same kind of bed.
Related Reading
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