Arctium tomentosum Seeds | Woolly Burdock
LATIN NAME: Arctium tomentosum
COMMON NAME: Woolly Burdock, Downy Burdock
Plant Profile
Woolly burdock is a biennial of the daisy family, native to Europe and western Asia, and it grows one to two metres tall in its second year, with stout, grooved stems and large, heart-shaped leaves that are white and cobwebby beneath.
The flower heads are globular, purple, and set in a burr of hooked bracts that cling to fur and clothing. It differs from greater burdock in its smaller heads, which are arranged in a loose, flat-topped cluster, and in the dense woolly hair on the underside of the leaves.
The burr is dense and rounded, and it holds seed into winter.
Science & Biotechnology
The hooked burr of Arctium is a classic example in studies of seed dispersal, and the mechanism has been copied in engineering design, most famously in the invention of hook-and-loop fasteners. Work on the genus has also compared the root chemistry of the different species, since the inulin content and the bitter sesquiterpene lactones vary between them.
Woolly burdock is less studied than greater burdock, and much of what is known comes from flora surveys and from weed science. Its pollen is a useful late-summer resource for honeybees, and the seed heads are taken by goldfinches in autumn.
Uses & Benefits
The young leaves and the root can be eaten in the same way as greater burdock, though the plant is rarely grown for the table and the root is thin and woody compared with cultivated gobo. It has a folk record as a blood cleanser and diuretic, in line with its relatives.
In the garden it is mostly a curiosity for the wilder corner, where the burrs are a nuisance to anyone walking past, and it is of most interest to botanists comparing the burdock species. It is a useful plant for a wildlife strip, where the seed heads feed finches through the winter.
The root is biennial and dies after seeding, so a colony depends on seed rather than on the same plant returning.
Growing from Seed
Sow in autumn or stratify for four weeks. Sow five millimetres deep in a free-draining mix, keep at 15-20C, and expect germination in two to three weeks. The plant makes a rosette in its first year and bolts in the second, so give it room and do not move it once established. A deep taproot means it resents transplanting, so sow where it is to stay.
It seeds freely and the burrs are hard to remove from clothing, so cut the heads before they ripen if you want to keep it in bounds. It tolerates poor, dry soil and grows best in full sun, which makes it a useful plant for a rough bank or a corner behind a shed.
Our Take
Woolly burdock is a plant for the curious rather than the tidy. Its burrs are a nuisance, but its ecology and its place in the genus make it worth a corner.
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