Comfrey is an introduced erect perennial herb, growing on hairy winged branching hollow stems from one to three+ feet high.
The leaves are both basal and stem. The lower basal leaves are broad and up to 8 inches long, ovate-lanceolate in shape with pointed tips and a base that tapers to a winged stalk. Leaves decrease in size up the stem the very upper leaves may be stalkless. The wings of the stalks continue down the stem creating the wing on the stem. Leaves are thick and rough, fine hair on both surfaces with longer hair on the underside veins, the margins and the leaf stalks; dark green surface on top, paler on the underside. Margins are without teeth and the veins have a distinctive net pattern.
The inflorescence is a leafless curving branched cluster (a cyme) which is terminal and can also arise from the upper leaf axils. These cymes are usually in pairs and the curve is said to resemble a scorpion's tail. Flowers are all on one side of the cyme.
The individual flowers have stalks with spreading hairs, leading to a green hairy calyx that has 5 lance-shaped pointed lobes. The entire calyx is much shorter than the corolla which is tube shaped, about 1/2 inch long with a distinct waistband where the upper section is a little more inflated. The color is whitish with purple tones to pink to purplish. The five lobe tips of the corolla are very short and spreading. The flowers are perfect but frequently the ovary is sterile. There are 5 stamens which cluster together at their tops around the single style.
Seed: Flowers that are fertile produce 4 brownish-black nutlets that are nearly smooth, angled on two sides with a concave base.
Toxicity and medicinal use - parts of the plant are toxic - see notes at page bottom.
Habitat: Comfrey grows from large coarse spindle shaped tuberous roots that have a black outer coating and produce a stout deep taproot. They are white, fleshy and juicy inside. In the wild it has escaped from cultivation and will generally be found in disturbed sites. When planted it needs plenty of moisture when young, rich soils, and does best under tree shade.
Names: The common name is from the Latin conferva meaning knitting together, referring to the plants medicinal qualities. The genus Symphytum is from the two Greek words - symphyo, meaning 'make to grow together' and phyton, meaning 'plant'. From those terms you may derive the meaning of healing broken bones - one of the former herbal uses of the plant tissue. The species officinale usually means 'sold in shops' referring to the use of this plant in herbal medicine. The author name for the plant classification - 'L.' is for Carl Linnaeus (1707-1778), Swedish botanist and the developer of the binomial nomenclature of modern taxonomy. All the various alternate common names have reference to the medicinal uses of the plant in old medicine. "Asses' Ears" refers the large soft lower leaves.
Above: The upper section of a plant with 3 cymes. Drawing of Comfrey courtesy of Kurt Stüber's Online Library.
Below: 1st photo - The green calyx has some purplish tints and is much shorter than the corolla. It has 5 lance shaped pointed lobes and those and the flower stalk and the cluster stalk are hairy. After the corolla of the fading flower falls away, the long style remains. 2nd photo - The five lobe tips of the corolla are very short and spreading. The 5 stamens cluster around the tip of the style
Below: 1st photo - The inflorescence usually has a pair of curving cymes which are said to look like a scorpion's tail. 2nd photo - Comfrey was growing in the Woodland Garden of Eloise Butler at the time of this photo - July 16, 1999.
Below: 1st photo - The underside of the leaf has hair on the veins and margins and shows off the distinctive net pattern. 2nd photo - After flowering, the curved cymes straighten out as the seed capsules are maturing. Not all flowers are fertile.
Below: One on the long lower leaves with its long winged stalk.
Below: 1st photo - The wing of the leaf stalk descends down the stem forming a wing on the stem. 2nd photo - Flowers that are fertile produce 4 brownish-black nutlets that are nearly smooth, angled on two sides with a concave base.
Notes: Comfrey has made its appearance in the Garden in the 1990s up through at least 2005 when it was mentioned in a Naturalists' report; it was found in the Woodland Garden along Lady-slipper Lane in the Marsh. It has not been recorded on any Garden census and is currently absent from the Garden. Comfrey is found in most of North America except the far north Canadian Provinces and the far south states of the U.S. Mostly absent also in the great plains states. It is a native of Eurasia, brought to North America by the early settlers from Europe. It is the only species of Symphytum found in Minnesota. The DNR reports its presence but they do not give a county breakdown.
Medicinal Use: Comfrey has been used for medicinal purposes for several thousand years, beginning in China and then spreading to Europe. An external poultice made from the leaves and a decoction or tincture made from the roots has been considered effective in reducing inflammation in the area of a sprain or fracture, allowing the body to heal - and from that ability came the derivation of the common and scientific names. The root also contains an abundance of mucilage and the chemical Allantoin in about 0.6% to 0.8% concentration. This is is used in ointments for psoriasis and other skin problems. Mucilage is used to create a medicine for intestinal disorders. The reputation of Comfrey in reducing inflammation, treating of wounds and burns is attributed to the Allantoin. Comfrey tea is said to ease bronchial and intestinal disorders but caution was advised in making this as when not in bloom the plant resembles foxglove which is a poisonous plant. Mrs. Grieve (Ref. #7) has much detail on the use of this plant.
Comfrey grows new leaves very rapidly so harvesting leaves for medicinal purposes from this plant provided a never-ending supply during the growing season as long as harvesting stopped in autumn, allowing the plant to build up reserves for the following year. Culpepper (Ref. #4b) wrote in the English Physician: "The great Comfrey helpeth those that spit blood, or make bloody urine. The root boiled in water or wine, and the decoction drank, helps all inward hurts, bruises, wounds, and ulcers of the lungs, and causeth the phlegm that oppresseth them to be easily spit forth... The roots being outwardly applied, help fresh wounds or cuts immediately, being bruised and laid thereto; and is special good for ruptures and broken bones; yea, it is said to be so powerful to consolidate and knit together, that if they be boiled with dissevered pieces of flesh in a pot, it will join them together again." Wow! He goes on to talk about soothing women's breasts during milk flow, to treating hemorrhoids and gout.
That these remarks, echoing the ancient Chinese, were still the belief in the mid 1600s when Culpepper first wrote is a testament to the ability of Comfrey to actually have some effects. Somewhat earlier in 1597 Gerard (Ref. #6a) wrote almost the same words in his Herball: "The rootes of Comfrey stamped, and the juice drunke with wine, helpeth those that spit bloude, and healeth all inward wounds and burstings." Among other uses Gerard lays out this tidbit: "The slimie substance of the roote made in a posset of ale, and given to drinke against the paine in the backe, gotten by any violent motion, as wrastling, or overmuch use of women, doth in fower or five daies perfectly cure the same; although the involuntarie flowing of the seed in men be gotten thereby."
Food and forage use: Young leaves are said to be edible when boiled and treated as a vegetable but John Lindley wrote in the 19th century "not, however, valued by persons of refined taste." The leaves have been used, even recently, as cattle fodder as they contain 35% protein. Cattle usually don’t care for it but will eat it when nothing else is available.
Toxicity: The leaves contain a toxic hepatotoxic pyrrolizidine alkaloid and in humans, ingesting large amounts of this can lead to liver failure. In addition the hairs on the leaves and stems irritate the skin. Gloves should be worn when handling the plant. Culpepper (Ref.#4b ) wrote: "The Great Comfrey hath divers very large hairy green leaves lying on the ground, so hairy or prickly, that if they touch any tender part of the hands, face, or body, it will cause it to itch."
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"