David Trammel's picture




- Common name, followed by Scientific Name, then (any) Alternative Names: (text) .

- Header Photo

- General Description of the Plant: (text) .

- Why We Grow This? (common uses): (text) .

- Historical Facts and Quotes: (text) .

- Can Be Confused With: (text) .

- Cautions and Hazards: (text) .



- Popular Variations and Cultivars (text) .

- Starting: from seed; from cutting; by root stock, rhizome, bulb, grafting; other (text) .

- Bedding Out: plant spacing, soil temperature, soil amendments, best rotation cycle. (text) .

- Best soil type: Loamy, moist; Sandy, well-drained; Mineral-dense, clay (text) .

- Sowing Season & Habits: Annual, Perennial, Biennial, self seeding, self pollinating, dioecious (text) .

- Plant Health maintenance: diseases, pests, treatments, cold shelters, interventions (text) .

- Companion Planting (text) .



- Signs of ripeness, over- and under-ripe (text) .

- Gathering tips. Gloves, techniques (text) .

- Preserving and Storage (text) .

- Post-harvest soil care and compostable wastes (text) .



- Nutritional Information: (text) .

- How to prepare before eating: (text) .

- Useful recipes and cooking hints: (text) .

- Historical dishes and meals: (text) .

- Non-Food Usages: (text) .



- How This Plant Propagates: (text) .

- Harvesting Seeds: (text) .

- Seed Storage: (text) .



- Green Wizard forum links

- Outside Links

- Helpful Books

- Contributors


If you have a plant that you grow on a regular basis and can take a few minutes to filling out the information, please post a reply to this thread with the name of the plant. I will make a new post, with you as author, with the template of this format. This will allow you to post the information.

David Trammel's picture

This looks like a really good article on this amazing plant.

Rest of the site looks like a good resource too.

Comfrey (Symphytum officinale Lepechin)
A.K.A.: Knitbone, Consound, Slippery root, Black root, Blackwort, Bruisewort, Wallwort, Healing herb, Gum plant, Knitback, Ass ear.

- Header Photo

- General Description of the Plant:
Comfrey is a perennial herb of the family Boraginaceae
Leaves are large, broad, ovate with pointed ends, rough and hairy to the touch
Back of the leaf is whitish or faded green in colour.
The root is dark, even black, thick and spindle shaped, tapering towards the end like a parsnip.
Tubular, bell-shaped flowers can be rose pink, cream, white, purple

- Why We Grow This? (common uses): .
Leaves and roots are primarily used as herbal medicine.
Spent or green chopped leaves can be used as green manure; when added to the compost pile they enrich the compost with minerals retrieved from deep in the soil.
Leaves can also be soaked in a small amount of water to make a vile-smelling compost tea for liquid fertilizer application.
Comfrey has been used in Jamaica as fodder in commercial goat and rabbit rearing.
Comfrey’s medicinal properties include anti-bacterial, anti-fungal, anti-inflammatory, anodyne, and astringent actions.
Root systems of comfrey can reach 2 yards in depth; they can break up and areate clay. Also, they draw up nutrients and minerals from the subsoil and make this enrichment available to more shallow-rooted companion plants.

- Historical Facts and Quotes:
U.S. American pioneers called it the "Healing Herb"

- Can Be Confused With:
Hogweed, Pokeweed

- Cautions and Hazards:
Vigorous Growth Habit: Common comfrey, like mint, grows rapidly and vigorously enough to spread where it is not wanted. In a small garden, it can be grown in a large, deep container and kept trimmed of flowers by a watchful gardener. Do NOT place root fragments or flowering stems on the compost heap unless you want them to grow like wildfire.

Modern Pharmacological Results:
Three studies are cited by Wikipedia in support of the idea that ingesting comfrey is not recommended by modern pharmacological agencies. Based on these studies, comfrey has been officially designated by the FDA as dangerous due to liver toxicity and carcinogenic properties. Warnings against ingesting it abound on the internet. One study performed on laboratory rats injected the pure, refined alkaloids of comfrey to deliver a dosage equivalent to a human being eating 100 pounds of leaf in a single day. This study concluded that comfrey causes liver toxicity. A similar rat study using concentrated dosages concluded that comfrey has carcinogenic properties.

Yeong M.L., et al.(1990), “Hepatic veno-occlusive disease associated with comfrey ingestion.”
Journal of Gastroenterology and Hepatology, 5(2): p. 211-4.
"FDA/CFSAN - FDA Advises Dietary Supplement Manufacturers to Remove Comfrey Products From the Market". Retrieved 2007-06-01.
PMID: 17118137 BMC Bioinformatics. 2006 Sep 26;7 Suppl 2:S16 Analysis of gene expression changes in relation to toxicity and tumorigenesis in the livers of Big Blue transgenic rats fed comfrey (Symphytum officinale).
Rode, Dorena.
"Summary of In Vivo Comfrey Studies". Retrieved 2008-02-20.

These studies aver that pyrrolizidine alkaloids (PAs) in comfrey are toxic to the liver. These PAs, can lead to veno-occlusive disease (VOD). VOD can in turn lead to liver failure. Comfrey, taken in extreme amounts, has been implicated in at least one death. In 2001, the United States Food and Drug Administration issued a warning against internal usage of herbal products containing comfrey.

Some commercially prepared products remove the pyrrolizidine alkaloids from comfrey. Merck claims its preparation called Kytta-Salbe is >99% free from pyrrolizidine alkaloids. SEE Grube et al. 2007. Phytomedicine 14: 2-10). Excessive doses of Symphytine, one of the PAs in comfrey, may cause cancer in rats. This was found by a testing procedure that injected the pure, concentrated alkaloid. The whole plant has once been shown to induce precancerous changes in transgenic rats.

Replication studies are not known to be pending at this time.

Readers are advised to use their own judgment and conduct their own research to decide how to best to benefit from the properties of comfrey.

Historical Uses: Prior to the 20th century, people have been ingesting comfrey for thousands of years: as a tea infusion, as a tincture and as a spinach-like wilted pot-herb in addtion to using it as a salve and poultice. Its use has often been documented in historical compilations of herbal remedies. In these pre-20th century texts, comfrey has been described as “sovereign, within and without”; meaning strongly effective either taken internally or as a topical application.

Comfrey has been used to treat several classes of ailments: respiratory, musculoskeletal, dermatological, gastrointestinal (GI) tract, renal, female reproductive issues, and dental. Constituents of comfrey include mucilage, steroidal saponins, tannins, pyrrolizidine alkaloids, inulin, vitamin B12 and proteins.

Comfrey has historically been used to treat:
broken bones, sprains, arthritis
bronchial inflammations, asthma, tuberculosis, sinusitis,
gastric ulcers, varicose ulcers, bedsores,
severe burns, skin rashes, sunburn, dry skin, dermatitis, cancerous growths,
insect stings, acne,
female disorders, post-birth hemorrhage,
soreness of the kidneys, soreness of stomach, soreness of bowels,
for lowering blood pressure and as a tonic blood purifier.

In the American midwest, pioneers called it the "Healing Herb." They used it to stem hemorrhaging in the lungs, nostrils and internal organs, to treat kidney problems, back pain and bladder infections. The tea was applied to the skin to heal most types of irritations and rashes.

One of the country names for comfrey was ‘knitbone’, signifying its striking value for treating bone disorders. The herb contains allantoin, a cell proliferant that speeds up the natural replacement of body cells. 21st century trials confirm that comfrey can mitigate pain and speed recovery from bone ailments.

PMID: 16510384 Adv Ther. 2005 Nov-Dec;22(6):681-92 Topical symphytum herb concentrate cream against myalgia: a randomized controlled double-blind clinical study.
PMID: 15638067 Phytomedicine. 2004 Sep;11(6):470-7. Efficacy and tolerance of a comfrey root extract (Extr. Rad. Symphyti) in the treatment of ankle distorsions: results of a multicenter, randomized, placebo-controlled, double-blind study.
PMID: 14518351 Fortschr Med Orig. 2002;120(1):1-9. Therapeutic characteristance and tolerance of topical comfrey preparations. Results of an observational study of patients
PMID: 17169543 Phytomedicine. 2007 Jan;14(1):2-10. Epub 2006 Dec 13. Efficacy of a comfrey root (Symphyti offic. radix) extract ointment in the treatment of patients with painful osteoarthritis of the knee: results of a double-blind, randomised, bicenter, placebo-controlled trial.

- Popular Variations and Cultivars
Russian comfrey (Symphytum x uplandicum) also known as Bocking 14 is sterile; it does not set seed; hence does not spread on its own as common comfrey will.

- Starting: from seed; from cutting; by root stock, rhizome, bulb, grafting; other (text) .
Common comfrey seeds itself. The Bocking 14 varietal is propagated by root cuttings.

- Bedding Out: plant spacing, soil temperature, soil amendments, best rotation cycle. (text) .
Comfrey can grow to a height of five feet or more if the soil is deep.
Offsets should be planted 2-3 feet apart with the growing points just below the surface.
Root segments should be buried about 2 inches deep. \
Keep the bed well watered until the young plants are established.

- Best soil type: Loamy, moist; Sandy, well-drained; Mineral-dense, clay
Comfrey will grow in any kind of soil except that which is too shallow or too wet. It does best where the soil is well-drained and deep, giving its taproot plenty of room to grow downwards. It is known to break up clay soils and make the nutrients in clay more available to itself and other palnts in the vicinity.

- Sowing Season & Habits: Annual, Perennial, Biennial, self seeding, self pollinating, dioecious Comfrey is a self-seeding perennial.

- Plant Health maintenance: diseases, pests, treatments, cold shelters, interventions
Comfrey is generally trouble free once established, although weaker or stressed plants can suffer from comfrey rust or mildew. Both are fungal diseases, They rarely seriously reduce plant growth and thus do not generally require control. However infected plants should not be used for propagation purposes.

Comfrey is a fast-growing leafy plant, hence nitrogen hungry. Animal manure, lawn mowings, and other nitrogen-rich materials can be used around it as a mulch. It is one of the few plants that will tolerate the application of fresh urine diluted 50:50 with water. NOTE: This nitrogen source should not be regularly used; urine salts can accumulate in the soil with adverse effects on soil biota and worms.

Comfrey ought not to be harvested in its first season; it needs to become established.
First year flowering stems should be removed as these will weaken the plant’s root growth
Comfrey should also be regularly watered until well established.
Pest predators such as spiders, lacewings and parasatoid wasps like to associate with comfrey. Do not clear cut when harvesting; leave a few plants standing. This encourages pest predators to stay nearby and eat harmful insects.
Russian Comfrey = Symphytum x uplandicum,is a naturally occurring hybrid of two wild species: Common Comfrey - Symphytum officinale and Prickly Comfrey - Symphytum asperum.

- Companion Planting
Comfrey for potatoes - freshly cut comfrey leaves should be wilted for a day or two, then laid along potato trenches about 2 inches deep. Avoid using flowering stems as these can root. The leaves will rapidly break down and supply potassium rich fertiliser for the developing potato plants.
Comfrey as a mulch- a 2 inch layer of comfrey leaves placed around a crop will slowly break down and release plant nutrients. it is especially useful for crops that need extra potassium, such as tomatoes and fruit shrubs such as gooseberries and currants.

Mature comfrey plants can be leaf-harvested 4 or 5 times per growing season. They are ready for cutting when about 2 feet high. This is usually in mid-Spring.
Well-grown comfrey can be harvested using shears, a sickle, or a scythe to cut the plant about 2 inches above the ground
After cutting, comfrey will rapidly regrow, and will be ready for further cutting about 5 weeks later. Some authorities say the best time to cut comfrey is shortly before flowering, when leaves are the most nutrient-packed.
Comfrey can continue growing into mid-Autumn, but it is best to stop harvesting in early Autumn. This allows the plants to build up winter reserves. As the leaves die back and break down in winter, nutrients and minerals are transported back to the roots for use the following spring.
When harvesting for the root, the gardener may choose to leave some root fragments in the soil to allow the plant to regrow over the the next two years.

Despite being sterile, Bocking 14 Russian Comfrey will steadily increase in size. It is therefore advisable to split it up every few years. Offsets can propagate more plants to be shared.
It is not easy to remove comfrey once established It is deep rooting and any root fragments left in the soil will regrow. The best way to eradicate comfrey is to very carefully dig it out, removing as much of the root as possible. This is best done in hot, dry summer weather, wherein the dry conditions will help to kill off any remaining root stumps.
Rotovation can also be successful, but may take several seasons.

- Signs of ripeness, over- and under-ripe
Yellowing, dropping, wilted, black spotted, white spotted or rusty-flocked leaves are not suitable for use.

- Gathering tips. Gloves, techniques
It is advisable to wear gloves when handling a large quantity of comfrey. Its leaves and stems are covered in hairs that can irritate the skin.
Comfrey can be trimmed of a few leaves now and then, or harvested as a whole, crown and top.
Clip off flowering stems to prevent self-seeding in a confined area.
If more growing plants are desirable, allow the plants to self-seed.

- Preserving and Storage
For dried leaf storage, first wash in cool water to free the leaves of dirt.
Trim off any yellowing spots.
Place the leaves and stems inside a large muslin cloth or a cotton/linen drawstring bag.
Hang the bag out of direct sunlight; preferably in a dark, airy, low-humidity place such as a ventilated shed or an air-conditioned stillroom.
In a week or ten days, the leaves should dry to a crisp, dark green, friable condition.
Place dried leaves in twists of parchment paper inside a sealed tin/stainless steel box or without paper in a large glass jar.

- Post-harvest soil care and compostable wastes
Comfrey leaf used as fertilizer is a significant source of potassium (K). Its leaves contain 2-3 times more potassium than farmyard manure. Its deep rooting habits make it serve as a general nutrient accumulator and mineral bank. Its leaves break down rapidly to a liquid since they lack fibre. A typical plant can yield up to 4 pounds per cut, 3 or 4 times per year. The C:N ratio of the leaves is lower than that of well-rotted compost; thus is does not pose a risk for nitrogen robbery when dug into the soil. mined from deep in the subsoil, tapping into reserves that would not normally be available to plants.

Compost activator - Comfrey in the compost heap adds nitrogen and increases heap heat. It breaks down into a dark sludge or liquid; balance this with a suffcient amount of fibrous, carbon rich materials.

Liquid fertiliser - Produced by two methods: rainwater rotting, or drained leaf stack.
1) Place leaves in enough rainewater to keep them covered and allow to sit lightly covered for 4–5 weeks to produce a ready to use 'comfrey tea' that has a vile odor.
2 Stack dry leaves under a weight in a container with a hole in the base. Allow the leaves to decompose into a thick black comfrey concentrate. Dilute the sludge at 15:1 before use.

Comfrey potting mixture - originally devised using peat, environmental awareness has led to a leaf mold-based alternative being adopted instead. Two year old, well decayed leaf mold will readily absorb the nutrient-rich liquid released by the decaying comfrey. In a black plastic sack alternate 3-4 inch layers of leaf mould and chopped comfrey leaves. Add a little dolomitic limestone to slightly raise pH. Leave for between 2–5 months depending on the season, checking that it does not dry out or become too wet. The mixture is ready when the comfrey leaves have rotted and are no longer visible. Use as a general potting compost, although it is too hot in K for tender seedlings.

- Nutritional Information:
The leaves are high in calcium, iron, protein, & allantoin – a cell proliferator, which assists in healing.

- How to prepare:
Use only fresh, green leaves.
Wash thoroughly
Check for signs of rust, mildew, yellowing, spots, or withering.
Remove any blemished parts of leaves

- Useful recipes and cooking hints:
To make tincture, place dried leaves in a glass jar and cover with Everclear vodka or similar high alcohol content beverage.

To make a fresh-leaf salve, wash and pat dry several leaves. Mash leaves with a pestle or wooden spoon dedicated to the purpose. Add food grade oil or butter to the mashed leaves. Keep refrigerated for use as a salve or poultice.

- Historical dishes and meals:
Confrey has been used to replace spinach for cooking.
Comfrey has been traditionally infused in boiling water to extract the iron content for a medicinal tea, or a cooling drink.

- Non-Food Usages:
Fomentation: For bruises, swellings, sprains, fractures apply a fomentation of the hot tea. It reduces swelling and eases pain. It fosters rapid bone healing and closes wounds almost immediately. The compound allantoin is a cell proliferant, which speeds up the body's natural healing process.
Poultice: Make a poultice of the fresh leaves and apply to ruptures, sore breast, wounds, ulcers, burns, insect bites, boils, and pimples.

- How This Plant Propagates:

- Harvesting Seeds:
- Seed Storage:

Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Asterids
Order: (unplaced)
Family: Boraginaceae
Genus: Symphytum
Species: Symphytum asperum Lepechin
Symphytum officinale L.
Symphytum tuberosum L.
Symphytum x uplandicum Nyman

- Green Wizard forum links
- Helpful Books
- Contributors

Additional Information:
Comfrey is native to Europe, growing in damp, grassy places such as riverbanks.
The “Bocking 14” cultivar of Russian Comfrey (Symphytum x uplandicum) was developed during the 1950s by Lawrence D Hills, founder of the Henry Doubleday Research Association.
This organic gardening organisation is named after the Quaker who first introduced Russian Comfrey into Britain in the 1910s) following trials at Bocking, near Braintree, the original home of the organization.

Other species include:
NOTE: All of these Symphytums are poisonous
Symphytum asperum (synonym: S. asperrimum), Prickly Comfrey, Rough Comfrey
Symphytum bulbosum, Bulbous Comfrey
Symphytum caucasicum, Caucasian Comfrey
Symphytum ibericum, Creeping Comfrey
Symphytum orientale, White Comfrey
Symphytum tauricum, Crimean Comfrey
Symphytum tuberosum, Tuberous Comfrey

- Outside Links
Comfrey Central - A Clearinghouse for Symphytum Information
British Columbia Cancer Agency on comfrey
ITIS 32025 2002-09-05.
NRM, Sweden 2002-09-05.
IPNI Symphytum 2002-09-05.
Flora of China 2002-09-05.

Balkan Ecology Project
Saturday, 27 February 2016
Comfrey - BELIEVE the HYPE!

Part 1. Introduction to Comfrey
A member of the Borage family, Comfrey - Symphytum spp. is native to Europe and Asia and there are 40 recorded species of Comfrey throughout that region. The plant most commonly referred to and used in gardens is Russian Comfrey - Symphytum x uplandicum, a naturally occurring hybrid of two wild species: Common Comfrey - Symphytum officinale and Prickly Comfrey - Symphytum asperum.
A few centuries back the hybrid Symphytum x uplandicum came to the attention of an original ecotrepreneur Henry Doubleday (1810 – 1902) and he widely promoted the plant as a food and forage crop. Years later, and after two world wars, Lawrence D Hills (1911–1991) would continue Henry Doubleday's Comfrey crusade.
In the 1950's Hills developed a Comfrey research program in the village of Bocking, near Braintree in the UK. The original trial site is on the plot of land now occupied by the Doubleday Gardens housing development. Lawrence Hills lived at 20 Convent Lane just around the corner of the trail site.
The area highlighted in red was the site of the Bocking trials. Today, it is home to the housing development named Doubleday Gardens in memory of Henry Doubleday. The red dot is where Hills lived.
At this site Hills trialed 21 Comfrey "strains" gathered from other growers around the country. He named the "strains" after the village Bocking and gave each one a number.
Strain fourteen was identified as being the most nutrient rich non-seeding strain and 'Bocking 14' began its journey into gardens far and wide across the world.
As a consequence of his research into comfrey and organic gardening, Hills founded HDRA (Henry Doubleday Research Organisiation). HDRA moved from Bocking to Wolston, near Coventry at the present site of Ryton Organic gardens in 1985, where today you can find ten acres of fully landscaped organic gardens. HDRA is now known as Garden Organic and is one of the worlds leading organic gardening organisations.
It's amusing to think how the chance offspring of two wild plants can have so much influence!
Regarding the other 20 strains, it appears all but 'Bocking 4' are lost. I'll be visiting Ryton Gardens in the summer to see if I can track down "the lost Bocking strains". If anyone has any other idea where they can be found please get in touch!

Medicinal Use - Comfrey has been cultivated, at least, since 400 BC as a healing herb.
The Greeks and Romans commonly used Comfrey to stop heavy bleeding, treat bronchial problems and heal wounds and broken bones. Poultices were made for external wounds and tea was consumed for internal ailments. Comfrey has been reported to promote healthy skin with its mucilage content that moisturizes and soothes and promotes cell proliferation. This plant is my first port of call if ever I need to dress a wound. Simply take a few leaves brush them together to remove the hairs and wrap them around the wound and apply light pressure. It's incredibly effective at stopping the bleeding, reducing the pain and healing the wound.

Biomass - Comfrey produces large amounts of foliage from late May until hard frosts in October or November. The plant is excellent for producing mulch and can be cut from 2 - 5 times per year depending on how well the plants are watered and fed. The plant grows rapidly after each harvest.
In our gardens we have Comfrey 'Bocking 14' located next to each fruit tree in order to have a renewable source of mulch just where we need it. We also grow in patches as part of our fertility strategy in the market garden and have patches in the wildflower meadows.(details below).

David Trammel's picture

Thank you for posting that. I'll get it moved up to the top asap.

There are quite a few typos in the text--I did not proof before posting--sorry about that, Chief.

kma's picture

Really good summary.

My data points:
-a poultice applied regularly helped Mr. KMA's elbow bursitis.
-I have lost three starts to chickens eating it so clearly I need to fence it off before it is well established. So you could add that in addition to goats and rabbits.