A FARM PROJECT:
COMFREY LEAF AND ROOTby
Richard Alan Miller, c1999
Latin Name: Symphytum officinale L. (Family: Boraginaceae)
Synonyms: Common Comfrey, Blackwort, Healing Herb, Bruiswort, Knitbone
Life Zone: The reported life zone for Comfrey is 6 to 25 degrees C., with an a annual precipitation of 0.5 to 2.7 meters, and a soil pH of 5.3 to 8.7 The plant grows best in a moist environment, and is found wild along rivers.
CROP - COMFREY LEAF AND ROOT (Symphytum officinale L.)
ADVANTAGES - Potential cattle food additive
MAJOR USES - Major food additive, cosmetic, pharmaceutical uses
CLIMATE REQUIREMENTS - 5.3 to 8.7 pH
19.2 to 106.2 inches annual precipitation
42.8 to 77.2 degrees F.NATURE OF PRODUCT - Sold as Leaf, Root, and Root Extract
WORLD & DOMESTIC VOLUMES - Unknown. Estimate world use for Leaf 80K ton. Domestic food and drug is 800 ton.
CURRENT SOURCES OF SUPPLY - South America, Germany, and Bulgaria
DOMESTIC PRODUCTION POTENTIALS - 1,000 ton/month/State as cattle food
COMPETITION - Oregon, California, Brazil, Germany, Bulgaria
EQUIPMENT NEEDS TO:
Grow - Irrigation, light cultivation, rotary mower, vacuum pick-up
Store - 200-lb. burlap bale, pallet load, heated storage
Process - Pellet mill, special dehydration systems (corn bin, hop dryer)
Market - Change in politics and belief systems
CULTURAL PROBLEMS - Grass control first two years
MARKETING PROBLEMS - New market for cattle feedlots
Description:
This hard perennial is native to Eurasia, and naturalized in North America. The erect growing herb can reach the height of one meter. Characteristically covered with a prickly pubescence, the plant develops flowers colored from white to purple, a thick, externally black root, and relatively large leaves.
Perennial, 30 to 120 cm tall, on thick brownish-black rootstock. Leaves and stems erect, with stiff hairs. Lower leaves to 25 cm long, petiole, lanceolate, hairy beneath. Upper leaves narrower. Flowers purplish, pinkish, or yellow-white, in crowded terminal cymes; appearing early Summer to early Autumn.
History:
Since certain strains of the Leaf contain almost 35% protein, vitamin B12, and the cell-proliferate allantoin, attempts have been made to extract it for human consumption. Comfrey is, however, an important feed in some parts of the world. It is also grown as an organic compost and mulch.
It reached the top of it’s fame in 1974, when Celestial Seasonings used it in many of their herbal tea blends. That year they imported some Comfrey from Brazil which was infested with Woody Nightshade. A number of people were poisoned, so Celestial Seasonings, in a vane attempt at damage control, immediately removed it from their blends.
What happened next was that Oregon State University and Washington State University conducted some studies to determine the content of oxalic acid and pyrillozine alkaloids present, thinking this is what poisoned Celestial Seasoning’s consumers. Their studies showed that there were toxic levels in both the leaf and root.
The two studies were flawed however, as the plant sources they used were over six years old, with no previous harvests of the leaf. Further studies would eventually show that there was essential not toxic value of alkaloids in leaf that had been cut from the plant prior to 10% flowering (much like Alfalfa).
Canada, then, without even studying the Leaf correctly, made Comfrey illegal for human consumption, just on the flawed studies from the two Universities. This severely limited the future use of Comfrey at that time.
If Comfrey is not cut at this stage of growth, then the Leaf tends to become more root-like in both alkaloid content and texture. In some private studies conducted with Honda Corp. in Osaka, their feedlots were three 60-story buildings. Not being outside, the cattle were rampant with disease. When fed a 605-Comfrey/40% Alfalfa pellet, however, virtually all diseases were eliminated.
Chemistry:
Both Leaf and Root have been used medicinally. The plant root has a large content of mucilage, allantoin, symphytine, echimidine, isobauerenol, beta-sitoosterol, tannins, and lasicarpine.
The tannins are responsible for the astringent properties of the plants parts, and the allantoin mucilage accounts for a demulcent activity. The pyrrolozidine alkaloids are potentially toxic, but not harmful in the small amounts ingested by humans.
Usage:
Comfrey Leaf is used as an external remedy as a poultice. In dehydrated and/or pellet form it makes a useful cattle fodder. It is also used as an adulterant of digitalis leaf. Rich in vitamin B12, amino acids, and proteins.
Comfrey Root is a demulcent used in cough mixtures in the form of a decoction. Cam be combined with Dandelion and Chicory for use in a non-caffinated “coffee” substitute.
Comfrey is also used in cosmetic products, such as Nexus Hair Conditioner.
Field Production:
Raising Seedlings: Usually always grown from rootstock, not seed.
Cultivation: Comfrey is cultivated from rootstock. Roots from an older field are quartered and cut into 3 to 5 inch lengths, by hand. They are planted 1.5 to 2.0 inches deep and one foot apart in rows (some recommended planting 4 inches deep, but this can lead to rotting before emergence); 17 to 20 inch furrows. Some 6 to 10 inches of rootstock can be taken from an established field every fourth year, with one acre reseeding five.
Fertilization: Likes nitrogen to encourage the lush leaf growth. Manure adds too many weeds. The taproot can grow to six feet within three years.
Irrigation: Comfrey likes a heavy irrigation which it sets up its root system the first year, probably as much as a five-day rotation on well drained soils.
Weed Control: Weed control is done by cultivation, however, when the field begins to mature somewhat an “umbrella effect” markedly discourages weed growth. The broad Comfrey leaves compete successfully with many weeds.
Insects & Diseases: None cited.
Harvesting:
Comfrey should be cut before 10% of the crop goes to flower. It cannot be dried in the sun because of high mucilage. Even pellet milled Comfrey will rot from the center. The best form of harvest is to cut at 6 inches from the ground with a side-bar cutter, attempting not to bruise the Leaf as this darkens it.
Root harvest can be done with potato digging equipment, taking care to pile and cover the Roots with tarps, or at least keep them from exposure to the drying effects of the sun.
Yields:
Yields in dry weight for a field established for four year or more can be five ton per acre on four cuttings. With heavy irrigation, up to six cuttings are available in some regions.
Tabin, S. , Berbeck, S., and Bobrzynski, T. The yields of sever ecotypes of Symphytum officinale [in Polish}. Hodowls Rosl. Aklim. Nassienn. 17: 505-511.
Drying:
Let the cut Leaf come to a 50% sun-cure wilt, and then pick it up with a flail-chop to be taken to a drying facility (i.e. Hop Kiln, Corn Dryer, etc.]. Tobacco dryers and plywood kilns are other alternatives for dryers. Comfrey is easy to grow, but the key to success with this crop lies in proper dehydration and handling.
Processing:
Besides processing the Leaf for the greenish powder, and harvesting the underground Root for drying, there is an opportunity to produce cattle feed alternatives as a 60% Comfrey/40% Alfalfa pellet. This constitutes a “whole food” for cattle.
Storage:
Both Leaf and dried Root should be kept in average room temperature and humidity for long-term storage. Store to eliminate the potential for insects, rodent contamination, and yeast and molds.
Marketing:
Buyers:
All Tech
Abco Laboritories Concord, CA
Berje Bloomfield, NJ
Abundant Life Supp. Dallas, TX
Bickford Flavors Cleveland, OH
AmeriSpice Inc. Camden, NJ
Aphrodisa Products Brooklyn, NY
Bio-Botanica Hauppauge, NY
Chart Corp. Paterson, NJ
Europa Foods, Ltd. Hauppauge, NY
G's Herbs Intl. Portland, OR
Herbarium Kenosha, WI
K.H.L. Flavors Maspeth, NY
Lebermuth Co., Inc. South Bend, IN
McAndrews/Forbes Camden, NJ
Penn Herb Co. Philadelphia, PA
San Francisco Herb Co. San Francisco, CA
Spice King Corp. Culver City, CA
Starwest Botanicals Rancho Cordova, CA
Weinstein Chem. Costa Mesa, CA
Whole Herb Mill Valley, CA
Quality Control:
The powder of Comfrey Leaf is green, almost inordorous, and has a mnucilaginous , weakly astringent tast. Product should be of more or less uniform color with little or no “browning” evident. As the flowers are edible, their inclusion is fine, except where high product uniformity is necessary.
Underground Comfrey Root is spindle shaped, branched, often more than 2.5 cm. thick, and 30 cm long. It shows external wrinkles, has a firm, horny texture, and dark color. The inside ranges from creamy white to a dark brown color. The Root is almost inodorous, and has a sweetish, mucilaginous, feebly astringent taste.
Powdered Comfrey Root is greyish brown in color with many small dark brown specks of outer bark in it. It contains a muscilage which is water soluble.
Regulatory Status:
Technical References:
Plaskett, G.L., “The preparation of protein concentrates from S. asperrimum (Russian Comfrey) for the non-ruminant feeds and human foods.” Food Chemistry 7 (2)
Hart, R.H., et. al. 1981 “Forage yield and quality of Quaker Comfrey, Alfalfa, and Orchard Grass.” Agronomy Journal 73 (4): 737-743
Mathieu, R.F. 1978 “Quaker or Russian Comfrey.” Herbarist 44: 16-25
De Padua, L.S. 1978 “Anatomy of Symphytum officinale L.” Phillipine J. Sci. 107: 41-50
De Padua, L.S., and Pantasico, J.B. 1976 “Histochemistry of comfrey, Symphytum officinale L.” Kalikasan 5: 351-356
Basler, A. 1972 “Cytotaxonomic study of the genus Symphytum L. of the Boraginaceae family. Studies on the predominatly north German plants of the species opf Symphytum asperum Lepech., Symphytum officinal L., and Symphytum X uplandicum Hym.” [in German] Bot. Jahrb. Syst. Pflanzengesch. Pflanzengeogr. 92: 508-553
Gadella, T.W.J., Kliphuis, E., and Perring, F.H. 1974 “Cytotaxonomic studies in the genus Symphytum. VI. Some notes on Symphytum in Britain.” Acta Bot., Neerl. 23: 433-437
Gadella, T.W.J., and Kliphuis, E. 1971. “Cytotaxonomic studies in the genus Symphytum. III. Some Symphytum hybrids in Belgium and The Netherlands.” Biol. Jaarb. 39: 97-107 AGRICOLA
Wcislo, H. 1972 “Karyological studies in Symphytum L.” Acta Biol. Cracov. Ser. Bot. 15: 153-163.
Hart, R.H. 1976 “Comfrey miracle or mirage? Crop Soils 29(1): 12-14
Duke, J.A., and Hurst, S.J. 1975 “Ecogical amplitude of herbs, spices and medicinal plants.” Lloydia 38: 404-410
Duke, J.A. 1979 “Ecosystematic data on economic plants.” Q.J. Crud Drug Res. 17(3-4): 91-110
Tanaka, H., Machida, Y., Tanaka, H., Mukai, N., and Misawa, M. 1974 “Accumulation of gultamine by suspension cultures of Symphytum officinal.” Agric. Biol. Chem. 38: 987-992
Hills, L.D. 1976 Comfrey: Fodder, Food & Remedy. Universe Books, NY
