Today’s featured plant is Comfrey, Symphytum officinale.
Comfrey is also known as common comfrey, knitbone (knit-bone, knit bone), knitback, knit bond, Quaker comfrey, gum plant, bruisewort, blackwort, black root, slippery root, boneset, consound, healing herb, salsify, and wallwort. *Note: This should not be confused with salsify/oyster plant (Tragopogon porrifolius), a garden root vegetable, which is not related.
Range and Identification of Comfrey
Comfrey is native to Europe through Siberia. It has been introduced to North America and other temperate regions, and can be found throughout much of the U.S. and up into Canada (see map). It prefers moist soil, and is often found as a garden escapee. Russian comfrey (S.x uplandicum) is a hybrid between common comfrey and prickly or rough comfrey and prefers drier ground.
The comfrey plant is a perennial, blooming in the spring/summer and dying back in fall/winter. It has a dense, clumping habit and grows up to 3 feet in height. Flowering stalks have leaves attached in an alternating pattern up the stem.
Comfrey flowers are borne in clusters at the top of the stem. They are delicate and bell-shaped, with only a slight aroma. The blooms measure about 1/2 ” in length, and come in an assortment of colors including white, pink and blue. The plant looks somewhat similar to foxglove, but foxglove flowers are larger and more showy.
Comfrey leaves are lance shaped, and may reach up to 1 1/2 feet in length. Like borage, the leaves are hairy and rough. (Comfrey is in the borage family.) As you can see, the veining is quite pronounced. On the leaf stem, there are small green wings that flair out on either side of the stem.
Comfrey roots have a branching habit, forming dense clusters and making them difficult to remove. They are brittle and break easily, and a new plant will regrow from the leftover bits. (Don't plant them in a spot unless you're sure you want them there.) The roots are dark brown on the outside and white on the inside and measure less than 1/2 inch in diameter.
Comfrey as Wildlife Habitat
Illinois Wildflowers list the faunal associations of comfrey:
For North America, little is known about floral-faunal relationships for this plant. According to MĂĽller (1873/1883) in Germany, nectar-seeking long-tongued bees are the primary pollinators of the flowers, particularly bumblebees and Anthophorine bees (Anthophora spp.); sometimes bumblebees steal nectar by chewing holes near the corolla bases of the flowers. MĂĽller also reported that honeybees, Halictid bees, and Syrphid flies (Rhingia sp.) would also steal nectar from the corolla holes that were created by bumblebees. Common Comfrey is somewhat toxic to mammalian herbivores and humans because it contains pyrrolizidine alkaloids. Over a period of time, these alkaloids can cause irreversible liver damage if the foliage and especially the roots are consumed in sufficient quantity. Horses, cattle, goats, and pigs are susceptible to being poisoned; apparently sheep are more resistant to adverse reactions.
Medicinal Uses of Comfrey
Comfrey contains pyrrolizidine alkaloids, which are naturally occurring plant toxins. As mentioned in the wildlife section, if consumed in large amounts, these can be toxic to the liver. There is a very detailed discussion of potential comfrey toxicity on the GardenWeb forums, in which the author states that based on available data, a human would need to consume nearly their weight in comfrey leaves to cause death. Clearly, this is not an issue under normal circumstances.
The leaves of comfrey have a much lower concentration of the toxins than the roots (almost none at certain times of the year) and are considered safer for internal use (comfrey root is no longer recommended by many herbalists for internal use). Backyard Medicine suggests that comfrey tea should not be used for more than six weeks at a time. It should also not be used if you are pregnant or nursing, or given to young children. *Note: Russian comfrey has higher pyrrolizidine alkaloid levels than common comfrey.
As its many folk names suggest, comfrey is one of the best herbs for healing broken bones, sprains, strains, bruises and tears. You can consume 1 – 2 cups of comfrey tea per day until the damage heals.
To make a fresh comfrey poultice to apply topically, dig up comfrey roots, clean and chop into short lengths. Blend with an equal amount of fresh comfrey leaf and just enough water to mix. Puree until relatively smooth. Apply to a piece of gauze and place over the affected body part and cover with breathable wrapping. Replace daily. (From Backyard Medicine.) Learning Herbs makes a poultice using just the leaves combines with a bit of water, pureed, and mixed with enough flour to thicken. For my cut fingertip, I just smashed a leaf, combined it with some dried yarrow, and bandaged it on.
The leaves can also be dried and infused in olive oil, and this oil can be made into a salve. If you don't have comfrey available, you can purchase a variety of comfrey products from a reputable herbal provider like Napiers.
Comfrey may also be used to treat circulatory conditions such as varicose veins and spider veins. (Need to try some salve this summer and see if I can chase away my spiders!) Backyard Medicine also suggest that it may be helpful for healing old wounds, such as surgical scars, and minor cuts. It is not recommended for topical treatment of deep cuts or puncture wounds, as it may cause the would to close at the top before it heal underneath, increasing the risk of abscess/infection.
9/4/2013 – I had a chance to check out the healing properties of comfrey first hand when I sliced my fingertip open recently. The cut was about one inch long and 1/8 inch deep at the deepest. It bled like crazy, so I knew the wound had been flushed out. I made a compress of fresh comfrey leaves and dried yarrow, which is antibacterial and also known for treating wounds. I kept a comfrey compress on it for 24 hours, and kept it covered for another 24. The cut happened Monday night, and this is what the wound looks like on Wednesday morning. No scab, no scar, no pain – which is great, because I still have a lot of canning to do.
One of the active compounds in comfrey is allantoin. This anti-inflammatory chemical stimulates cell proliferation and supports the immune system. The plant also contains tannins, mucilage, gum, resin and volatile oil. The roots were commonly used for bronchitis and other chest complaints, and for stomach issues such as ulcers, but now other herbs are generally recommended. The Holistic Herbal discusses more of these other uses.
As always, any medical information is for informational purposes only. Always exercise caution when using any wild plants and make sure you have positively identified the plant.
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This post is written in collaboration with Napiers as part of the Weekly Weeder series.
Becky says
Yes, please continue this series! Very informative!
Jennifer says
Just wanted to add that in addition to it’s medicinal benefits for humans, comfrey is an amazing plant in the garden. It is a dynamic accumulator. This means is has the ability to draw up nutrients in the ground and concentrate them in it’s leaves. It has a long tap root, so it can reach waaaaay down deep and get to nutrients that are not normally available to most plants. We have comfrey everywhere. We boarder our whole garden with it to keep out the encroaching weeds. We harvest the leaves and use them as mulch in the vegetable garden and forest garden. They are great companions for most fruit trees as well. We also add them to compost pile to accelerate breakdown and make compost tea with them. The flowers attract beneficial insects and we feed some to our rabbits and pigs.
CommonSenseIdea says
Thanks, Jennifer! My patch is small, so I haven’t used it for that yet (the fertilizer qualities). I remember reading about it a while back but forgot to mention it in the post.
Karen says
As we are planting our potatoes this spring I will be placing a scoop of dried comfrey with each potato hill. I think this will help the plant have the nutrients it needs as it grows.
D'ANN says
I love my comfrey both cooked as any leafy greens, and as an addition to my smoothies!
Matteo says
Be careful, it’s toxic to the liver.
It shouldn’t be taken orally for extensive periods of time.
Barb @ A Life in Balance says
I’ve been using comfrey as a mulching agent and fertilizer. I wish I had known about its ability to help heal sprains when I severely sprained my ankle at the end of January.
Amanda says
We were warned in our Home Herbalist class to be very careful with comfrey. That it encourages healing to the point that it’s dangerous. If you have an open wound, do NOT use comfrey! It can actually cause the top layer of skin to heal over, while the wound inside does not. But, it is very good for things like bruises, or under skin injuries.
CommonSenseIdea says
Amanda, thanks for taking the time to reiterate this. I’ll make sure it’s clearer in the post.
amy says
I’m wondering if you have heard about using comfrey to regrow teeth? and what do you think of it? I saw it on Natural News.
Laurie Neverman says
It’s possible, but I don’t generally trust anything I read on Natural News without double checking their sources. I’ve clicked on their so called sources in the past, and found that they linked to either completely unrelated articles, or articles that did not say what they said they said.
Sharon - SimplyCanning.com says
Hi Laurie, I’ve been researching Comfrey and decided to check what you had to say about it. The article is older so I just thought I’d see if you still feel it would be safe for ingestion for animals. I’m looking for fodder for both our chickens and bunnies. And of course composting as well.
Thanks for your thoughts.
Laurie Neverman says
Hi Sharon.
Yes, I still feel that it is safe for ingestion as a part of their fodder (up to 10% for chickens, not sure how much for bunnies). I wouldn’t feed it exclusively, but I wouldn’t feed any one single food exclusively. Also, some animals are less than thrilled to eat it. It helps to wilt it for a day so it’s less prickly before feeding.
Eve says
I have been using comfrey since I broke my foot in Hawaii in 1979. I had no open wound. I wrapped my foot in a poultice and immediately felt a cooling and the swelling went down immediately. I did not know about the gardening support but now i know why the vegetables I rotate near my comfrey are always the healthiest. Preparing to use as a border for garden. Fall is best time to transplant. Thank you.
Laurie Neverman says
Thanks for sharing your experience, Eve.
teresa moulton says
Thanks for the information on Comfrey.
Laurie Neverman says
You’re welcome.