Burdocks are large leaved, coarse plants of waste places, erect and biennial. First year plants have a rosette of basal leaves.
Leaves are egg-shaped, lower leaves with heart-shape bases, sometime entire or with a few blunt teeth.
Flowers: Unlike many composites in the Aster family, the genus Arctium has no ray florets. The pink to purplish disc florets (up to 40+) occur in bristly heads. Each disc floret has a pinkish corolla, cylinder in form with 5 upward lobes. Florets can occasionally have white corollas (photo below). Inside the corolla are the dark purple anthers which create a sheath about the white style which is exserted above the anthers. The style has a bifurcated tip (split in two parts). The bristly effect of the outside of the flower head is from the green phyllaries (bracts) of the flower head which have inward curving hooks at their tip. The phyllaries are arranged in 9 to 17 series with their bases appressed to the flower head.
Fruit: At maturity these hooked phyllaries turn the flower head into a clinging, prickly bur which contains several small brownish cypselae (seeds of the Aster family which resemble achenes). Dogs are quite familiar with burdock burs.
Comparison of the two species: The main visual differences between these two species is:
Stem: A. lappa can grow to 9 feet high with branching, A. minus usually no more than 5 to 6 feet, little branching, although a rather large specimen is seen in the last photo below.
Flowers: A. minus has flower heads 1/2 to 1 inch wide, either stalkless or on short stalks and the flowers stick up above the bracts, whereas A. lappa has heads 1 to 1-1/2 inches wide, on long stalks the upper bracts are as long as the flowers.
Cypselae: In A. minus they are dark brown or with darker spots. In A. lappa they are a lighter brown with darker spots.
Leaves: In the lower leaf stalks, A. minus have a hollow core with a noticeable furrow on top, whereas A. lappa are solid with groves and have a much deeper furrow and clasp the stem.
Habitat: Burdocks grow in full sun to partial shade, in a range of soil conditions, usually along rights-of-way, paths, woodland edges. Lesser Burdock is invasive.
Names: The genus Arctium is an old name, from the Greek word arction, which was the name of a plant known to the Greeks and to the Romans (Pliny) as arcturus. The species minus, simply means 'smaller' and lappa is the Latin name for a 'bur'. The author names for the plant classification are: ‘Bernh.’ is for Johann Jakob Bernhardi (1774-1850) German botanist, Professor of Botany, director of the Botanical Garden at Erfurt. His herbarium collection is now in the Missouri Botanical Garden Herbarium and, of course, 'L.' is for Carl Linnaeus (1707-1778), Swedish botanist and the developer of the binomial nomenclature of modern taxonomy.
Above: 1st photo - Lesser Burdock with the flowers above the bracts. Note the bifurcation of the white styles. 2nd photo - Note in the disc florets, the cylinder shape of the corolla with five upward pointing lobes, which surrounds the dark purple anthers, which in turn, envelope the white style.
Below: 1st photo - The developing buds of Lesser Burdock. 2nd photo - this plant has very short stalks or none at all. 3rd photo - an example with longer stalks - about the maximum length normally seen.
Below: 1st photo - A lower leaf of Lesser Burdock with its hollow stem. 2nd photo - The grooved stem of Lesser Burdock
Below - White Flowers: Burdock may occasionally have white corollas on the florets.
Below: 1st photo - Burs: Once the flower head matures the seed heads look much the same. 2nd photo - Lesser Burdock is generally a smaller plant but see last photo in this series below.
Comparison of Lesser Burdock with Greater Burdock.
Flowers: A. minus has flower heads 1/2 to 1 inch wide, either stalkless or on short stalks and the flowers stick up above the bracts, whereas A. lappa has heads 1 to 1-1/2 inch wide, on long stalks the upper bracts are as long as the flowers. Flowers themselves are identical.
Leaves: In the lower leaf stalks, A. minus are mostly hollow with a noticeable furrow on top - (note furrow in photo above left and below), whereas A. lappa are solid with groves but not the deep furrow and clasp the stem.
Below: A large lower leaf of Lesser Burdock. Note the furrow on top of the stem.
Below: While one may not want to purposely plant Burdock - it can make an impressive impenetrable hedge as this group of Burdock shows.
Plant size: A. lappa can grow to 9 feet high, A. minus usually no more than 5 to 6 feet, which this specimen slightly exceeds, topping out at 6.5 feet.
Notes: Burdocks are European imports that have naturalized themselves throughout North America except the far north. That said, there are a great many counties in Minnesota, principally in the western half of the state, that do not report A. minus. A. lappa may be in Minnesota, but the MN DNR does not report it on their county surveys. Burdock is not indigenous to the Garden but has been around many years. Martha Crone listed A. minus on her 1951 Garden census. There is usually a plant or two outside the Garden Fence near the old bike rack and the rest room.
A third species of Arctium exists in Minnesota, Arctium tomentosum Mill., known as Woolly Burdock due to hair on the leaves and the flower heads. It is known only from Kittson County. The three species of Arctium covered here are the only three found in North America, although there are about 10 species in the world.
Eloise Butler wrote in 1911 in her unpublished work - The Wild Botanic Garden: "The large, coarse, basal leaves of the weed burdock, novices are apt to mistake for “pie-plant.” A taste of the leaf would convince them that this disagreeable composite is no relation to the acid rhubarb which is allied to the bur-less docks, just mentioned. The burdock is a naturalized biennial from the old world. The seeds that sprout this season form the big leaves. Next year a large, bush-like plant will develop, crowned with pink heads surrounded with row upon row of barbed grappling hooks.
We can admire the symmetry of the rank growth and rejoice with the little girls who furnish their doll houses with elegant sofas, chairs, and bureaus made of the burs; but before the seeds mature, the plant should be uprooted and burned to protect dogs and cattle from the discomforts of stinging prickles and matted fur, not to speak of the mortification of people, who fine themselves the “observed of all observers” on returning from an autumn walk, festooned and kilted by these “sticktights.”
Lore and uses: It may surprise one to realize that this rough looking plant has important food and medicinal uses - both in America and in the Old World from which it came. Shakespeare makes reference to the plant in three plays. Here is a brief summation of uses:
Medicinal: The medicinal use of Burdock is thought to be more important than the food use. Dried root from first year plants was considered an official drug and one of the best blood purifiers. It was also used in treating skin diseases, especially in the treatment of eczema. Seeds and leaves were also used. Leaves provided use as a poultice and for an infusion. In North America the seeds were considered very important to make a tincture and extract for chronic skin diseases. Hutchins (Ref. #12) gives specifics on process and some uses. She also mentions the wide use of the plant in the folk medicine of Russia. One particular example from the old days is Burdock oil, called "Repeinoe Maslo" in Russian, used as a hair tonic to strengthen and encourage the growth of new hair. This use was in fact somewhat confirmed by a line in the first novel of contemporary Russian poet Yevgeny Yevtushenko, (Wild Berries 1981), in which he writes "Once Karyakin, the haberdasher, came by and examined the painting for a long time. Then smoothing his hair, greased with burdock oil and cut "in Parentheses," he asked Barkhotkin senior . . ."
Culpeper (Ref. #4b) has much to say about Burdock in The English Physician, including this - "The leaves applied to the places troubled with the shrinking of the sinews or arteries, give much ease. The juice of the leaves, or rather the roots themselves, given to drink with old wine, doth wonderfully help the biting of any serpents; and the root beaten with a little salt, and laid on the place, suddenly easeth the pain thereof, and helpeth those that are bit by a mad dog. The juice of the leaves being drank with honey, provoketh urine, and remedieth the pain of the bladder."
Food: Originally brought to the new world as a food source, it can still be found at some markets in the old world and in specialty organic food stores in the U.S. In Japan, cultivars are grown for food market purposes. The root, leaves and stem are useful as foods. The pith of the root and of the leaf stalks can be cooked as a vegetable or used as a potherb. The root is to be collected in the fall from first year plants and the leaf stems must be stripped of all the outer rind. Collect leaves before the flowers form. In eastern Asia, sliced root is used for stir-fry, especially good with sesame seed and soy sauce. The young stalks when boiled are said to resemble asparagus in taste and stalks and young leaves make a pleasant salad. The root is a long taproot, often up to 2 feet long and of 2 to 3 lbs. weight. Roasted ground root can be used for a tea and as a coffee substitute.
You can read much additional information in Fernald (Ref.#6), Hutchens (Ref. #12), Harrington (Ref.#9), Tilford (Ref. #39), and Mrs. Grieve. (Ref.#7). Hutchens and Mrs. Grieve are particularly good. And finally I might add another opinion, remembering that tolerant people consider that a "weed" is simply a plant growing where you don't want it, Ada George (Ref. #6b) wrote in 1914 in her book A Manual of Weeds, "The presence of one of these huge weeds in flower and fruit should be considered a disgrace to the owner of the soil so occupied."
Thoreau wrote in his journals ". . . with the fruit of the burdock, with which children are wont to build houses and barns without any mortar; both men and animals, apparently such as have shaggy coats, are employed in transporting them. I have even relieved a cat with a large mass of them which she could not get rid of, and I frequently see a cow with a bunch in the end of her whisking tail, with which, perhaps, she stings herself in her vain efforts to brush off imagined flies."
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Identification booklet for most of the flowering forbs and small flowering shrubs of the Eloise Butler Wildflower Garden. Details Here.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"