Learning About Comfrey

Like many gardeners, I have comfrey in my garden. Mostly I use them as a green accent to the other features of my garden, but I do remember occasionally to chuck a few leaves into the compost, or give some to the chickens. Until recently, though, I was working under the impression that there was only one type of comfrey, despite the fact that my comfrey plants were clearly of two different types. Three of the plants I transplanted grew very long leaves, and have never flowered that I noticed. The fourth plant I keep in a pot; it has short leaves, flowers madly every year, and clearly spreads via seeds, if the plant starts in the dirt under the pot are any indicator. Everyone I asked about the phenomenon, though, said they only thought there was just the one type.
 
So I finally let my fingers do the walking, and after some interesting reading, I found the answer. Google to the rescue: there ARE different types of comfrey!

About 40 species or so, to be exact. It's native to Europe, but has spread to Asia and North America (after being introduced in the 17th century), and is probably a feature in gardens all over the globe now. For the sake of simplicity, though, I'll stick to the ones you are most likely to find available for your garden: "True" Comfrey, and "Russian" Comfrey.

Here is a good photo to compare the general looks of the two varieties. We have three tomato plants flanked by two pots of comfrey. The far left pot contains the True Comfrey, discernible by its small, rounder leaves, its clumped up growing habit, and its tendency to flower abundantly. The pot on the far right contains Russian Comfrey. Its leaves are much more elongated than that of True Comfrey, it doesn't grow in such a tight clump, and although it can also flower, my particular plant hasn't yet (but there is still time for that to change, of course).

Russian Comfrey (Symphytum x uplandicum) is actually a hybrid, bred from True Comfrey (Symphytum officinale) and another variety called Rough Comfrey (Symphytum asperum). It is ideally used to create large amounts of biomass for permaculture gardens, composting, liquid fertilizers and as animal feed. While comfrey has a range of different colored, bell shaped flowers, this variety usually has blue or purple blooms. There are at least 21 cultivars of Russian Comfrey, although it seems that most people have "Bocking 14", or possibly "Bocking 4". These hybrids do not produce fertile seeds, and thus spread via root division.

True Comfrey spilling it out of its pot. You can see
it has seeded itself into the ground below it as well.

Gerard in his Herball gives an unusual use for the root juice in ale; it is "given to drinke against the paine in the back gotten by wrestling, or overuse of women."

True Comfrey (Symphytum officinale) is the species originally used in traditional herbal medicines (officinale, or officinalis, means "of the [herbalist's] shop") which has smaller leaves, grows a little less vigorously, and reproduces from seeds. Ideally, it is used medicinally, but True and Russian comfrey are interchangeable for that purpose. It was used to treat a number of ailments, including broken bones and sprains, has a chemical called allantoin, which is thought to encourage cell growth and repair, and has anti-inflammatory properties. It is probably best used topically, as ingesting it can cause potential damage to the liver.

The traditional name of Comfrey is "Knitbone". "Boneset" was also used, but I personally don't use it to avoid confusion, as Comfrey is NOT to be confused with the actual Boneset, which is a totally different plant (Eupatorium perfoliatum).

Bell shaped comfrey blooms, in white. They can also be
pink, blue or purple, and sometimes striped.

Comfrey is a hungry garden plant, so plant it with that in mind. Give it plenty of nitrogen rich fertilizer and water well, especially on hot days (otherwise it will sulk and look very sad indeed). It comes back year after year, but is only actively growing during the temperate months, dying back in the autumn (unless you have my true comfrey plant, which never seems to die back...the Russian comfrey dies back to the ground though, so it's at least predictable.)

Comfrey grows prolifically, and can be hard to control if it really likes the spot you put it in. Luckily, disposing of excess comfrey is easy: just throw the leaves in the compost bin (this works well for slow to start bins, as the leaves are a compost activator), or plant the fresh leaves right in the hole with the root ball of your garden plants for a nutrient boost at the roots (just don't plant the flowering stems, as those will take root). If you're feeling particularly adventurous, try making your own liquid fertilizer from comfrey: Harvest the leaves from the base of the plant (you may wish to wear gloves, as the hairy leaves are prickly, and may irritate your skin), chop the leaves up, and pack them into a waterproof container. Use a container with the lid, as it's a smelly process. Weight the leaves down with a brick. They will breakdown over time and release a dark brown liquid. Add fresh leaves to the bucket to continue the process, and collect any liquid that gathers at the bottom. This liquid will need to be diluted 10:1 (10 parts water to 1 part comfrey liquid). It is a potassium rich fertilizer, which is excellent for encouraging flowers and fruit set in your plants.

When dried, comfrey has a high protein content and is low in fiber, which is excellent for non ruminant livestock (like pigs and chickens, both of which have difficulty digesting roughage). If you are using comfrey for livestock feed, be sure to harvest often and never let it flower. Remove the flowering stalks (which have double the fiber and much less protein). Because the leaves are hairy, they may be unpleasant to your animals at first, so try wilting them for a day to see if that makes it more palatable. As usual, though, use your common sense: don't feed your animals on nothing but comfrey. It's a good feed supplement, but not meant for continuous feeding! (And let's face it, the animals also appreciate a range of foliage to eat.)

I hope this has provided a decent introduction to the comfrey plant, for all gardeners, so the next time you're cruising the nursery, or buying seeds online, give it a try and see how it goes. If you have experiences with comfrey use, please feel free to share them in the comments section.

Happy Gardening!

Sources:
http://www.waldeneffect.org/blog/Feeding_comfrey_to_livestock/
http://www.waldeneffect.org/blog/Types_of_comfrey/
https://en.wikipedia.org/wiki/Comfrey