When NOT to plant comfrey

Henry Jabel wrote:

Christopher Weeks wrote:It looks like there might be a valid claim to accumulating and distributing potassium and silicon, and boron to a lesser extent. And it does produce just an awful lot of foliage, so the gross physical reasons that chop-n-dropping anything is good, apply especially to comfrey even if dynamic accumulation isn't a legit reason.

Finally found the spreadsheet on the desktop:

K: Lambs quarter is 87100 vs Comfrey's 1870
Si: Horsetail 97000 vs Comfrey's 1
B: Dandelion 125 though there doesn't seem to much info on B

Cant seem to find a link to where I got this all in a handy spreadsheet and I cant seem to attach .xls sadly

On the subject of lamb's quarter, we had a big swath of it come up last year and grow up to 8 feet tall in that section. At the end of the season, we cut it down and mulched that area with the fallen plants. The foliage disappeared quickly, but the thick woody stems have been left behind, getting spotty and moldy but not composting down much at all. Also, the root ball and the stem below where we chopped has not broken down, so that leaves sharp stems sticking up out of the ground. (I have a toddler, so sharp pointy things sticking out of the ground aren't super desirable.)

Because we didn't chop it throughout the season, I'm not sure how lamb's quarter does when it's chopped younger. Does anyone have personal experience with this?

It's a trade-off, I think. Comfrey is easier to chop and drop (because it disintegrates entirely relatively quickly, as I observed last year) but propagates by root, so is hard to get rid of. Lamb's quarter might be easier to get rid of (chop before seeding), but then you have to deal with long woody stems (and even the small stems don't go away that fast). If that's what you want, it might be a more effective provider of potassium. You could chop just the young, tender shoots and leaves to mulch with. But that seems like more work to me. It's also a different type of root--more like a fibrous root ball with lots of fine hairlike roots, rather than long taproots like comfrey.

So, perhaps--comfrey only in areas you won't be disturbing the soil much, chop and drop there. If needed, amend the same area also with liquid teas/drenches/foliar sprays made from lamb's quarter, dandelion, and others. Though again, if your goal of a self-sustaining and self-regenerating polyculture that doesn't need much human intervention to succeed, that's more work than desired.

Based on your research and observations, Henry, what I'm hearing is that I shouldn't rely only on comfrey to be a cure-all to meet the needs of the surrounding plants. That seems like fine common sense as well. I'm always suspicious of anything claiming to be a panacea for all ills.

I'll chime in with my experience:

I'm in what was traditionally cool wet summers, though both of those things are changing, so I planted my sterile comfrey in a few sunny places.  Specifically, I planted it along the north edge of what was the annual bed, thinking it would be good for chop-and-drop.  Don't do that!

It does not set seed, but the roots are expanding into the beds.  The north bed is now planted with asparagus to minimize bed disruption.  Despite a trench between the beds, the comfrey is invading, and asparagus does not win that battle.

Also, I have noticed the currants north of the comfrey dying back.  I had assumed they had reached end-of-life, as they were here when I got the garden, but it could be comfrey-related as well.  (I have vast quantities of currants, so it's not a big deal, but annoying.)

I do get a ton of mulch, probably three cuttings a year if I'm feeling vindictive, and they bounce right back.  Also, bees love it (I have to cut it after dark as they swarm it).

In retrospect, I'd plant the comfrey in shadier places like under the big apple tree, to keep grass down, etc.

I remember reading something about Comfrey not being a dynamic accumulator. Probably somewhere on permies. I had seen good results using it as a tea ferilizer. I decided that in my garden it didn't matter what action made it work, and kept using it.

There is the topically medicinal properties of Comfrey that I believe is a benefit to the garden. It has allantoin which incourages cell proliferation.

Will comfrey of either variety grow back from any of the finer hair like roots that are left in the soil?  I'm attempting to relocate several plants that I realize should not have been planted in my garden boxes.  It is about 2-3 yrs old and roots are pencil sized but many are finer and it is hard to really tell if they are from nearby perennials or from the comfrey. Should I remove them all?  

Joylynn Hardesty wrote:I remember reading something about Comfrey not being a dynamic accumulator.

The main arguments about comfrey NOT being a dynamic accumulator are: the NPK value is not super high at about 3-1-5; not always grow deep roots; heredeep roots are for drought resistance not nutrient uptake. Even if true, that doesn't mean comfrey isn't an amazing plant because one needs to take into account other factors. If in the right climate, comfrey can be harvested multiple times with little care as an perennial. In that case, it sure beats a hypothetical super plant with very high NPK but with low yield of total biomass per acre, easily gets out competed or needs to be replanted every year.

I got some comfrey starts last year. I am worrying about it out of control since I have chickens.

May Lotito wrote: I got some comfrey starts last year. I am worrying about it out of control since I have chickens.

I have one patch of Russian Bocking 14, but I also have starts from root cuttings indoors from Russian Bocking 4 with the intention of using that patch to supplement my chicken's feed.  I'm finding a lot of things on my land can go to the chickens if I don't have any other use for it which is convenient.

Another word on official comfrey and how I grow them. Today I noticed one of the seed-grown comfrey plants overtaking some barley that I had planted. There had just been a short rainstorm, so the soil was quite wet. I reached under the leaves and grasped the root, and gently pulled the entire plant up. Seedling grown plants make a neat, straight taproot in their first year, which has less issues leaving pieces in the soil. I am cutting off the crown to replant elsewhere, and preserving the root for medicine.

I planted my Comfrey last year. This year it is tall and had lots of purple flowers. Though we only use it for injuries, my chickens get a leafy treat every day now, and they love it so much. If I did not remove a leaf for each chicken every day, I could see where these healthy plants might get out of hand really fast. For the record, I planted it pretty close to my cherry tree, so I hope that will not be a problem. I had not thought that through when I planted it.

I hope I didn't make a mistake when I transplanted a ton of it around all my fruit trees!  It was growing in a keyhole raised bed somehow (I didn't put it there) and I wanted it elsewhere. I think I have both varieties but not sure. The original plant was a gift and it never spread beyond where I put it without my help. I have it growing all along my fencelines and under the orchard trees, partly to crowd out the grass, partly to use as chop and drop, but mostly to feed it to my goats!

Another thought on its medicinal properties in the environment.   I read somewhere,  likely in a blog or book of Richo Cech's, that someone used comfrey poultice to help heal a tree that goats had munched bark from.   It definitely serves as a cell proliferant.  I did a presentation at a suture conference on herbs used in trauma and wound care.   Comfrey should never be used on a deep laceration as it makes the wound heal from the top down, potentially sealing in infection.   Also should not be used in fracture care unless you know bone to be in correct position because it will start the knitting process as it lies.

Some detailed info from the past:

https://soilandhealth.org/copyrighted-book/russian-comfrey/

index for the library, there's more on Comfrey:

https://www.soilandhealth.org/wp-content/uploads/01aglibrary/01aglibwelcome.html

As far as comfrey being hard to eradicate, I have done it unintentionally several times.
Shade works. Deep mulch such as wood chips works. Lack of water often works.
Comfrey doesn't much like it here. It's dry here and somewhat cool and shady.
I've had it for years and it sort of struggles along, just enough that I can make salve every few years (that's plenty!) and occasionally share a root or try to propagate some to spread it around my yard.
I have put it adjacent to pre-existing fruit trees, within three feet, and it has not seemed to interfere.
Where it survives it works for weed suppression, but it barely spreads, so it doesn't do it for a large area.
I don't know what variety I have. I think it's a sterile one; I have not seen seeds that I recall. I have seen seeds on other comfreys at other times, so I think I would notice.
I probably got this batch from Horizon Herbs, though that doesn't say much because they have both officinalis and x uplandicum.

The only place we planted Russian comfrey where it did NOT thrive was in a spot where 2 trees had previously died. The comfrey lived, but is not as big as others. It must not be a great spot to grow anything!

The one spot I really regret is planting one right beside a rhubarb. They are now competing for nutrients and comfrey seems to be spreading towards the rhubarb.
Another bad spot is near a young fig tree. The tree doesn't seem to be thriving, at least not yet. If anything, the comfrey is twice as big as the tree.

I plan to plant some comfrey closer to the compost pile in the future. That way I can chop and drop some leaves right in the pile!

Our comfreys seem to do well both in full sun and relatively shady areas. We had one common comfrey originally which actually died. All we have now is Russian comfrey. One did spread on accident due to digging around it - likely broke off some root fragments. It didn't spread super far, so we left it.

I think the plants are actually quite ornamental, especially in mass plantings or some sort of a border, and I would rather have more comfrey than grass.

The author from Nantahala Farm wrote 2 very detailed books on comfrey - https://www.nantahala-farm.com/farm.shtml. She is definitely a huge comfrey fan.

Overall, I recommend NOT planting it in a very small garden, good soil (save those spots for less tough plants), or too close to other plants.

How much water do people find their comfrey needs?

Where I want to garden is fairly dry, supposed to get  18" a year but I think with climate weirding it could now get less, plus summers are hot and almost rainless, with rain falling in large storms between September and April.

I won't be there to irrigate, and wonder if it's worth even trying comfrey. So far I've been throwing seeds around to see what will survive, but I'm a bit wary of that with a seed-producing comfrey in case it thrives too well vene on such limited water!

Jane, in your circumstances I would plant it where it would get sun in the spring while the soil is still moist and shade in the summer while it waits for more rain, if that's possible.
I doubt it will thrive "too well". But you could plant a sterile variety if that's a concern.
I think it's worth a try. For some medicines it's irreplaceable.

Hmm, good thought. Maybe under one of the grape arbours would work. It would still get some morning sun in summer, but shade during the hottest parts of the day. That area also gets run off from one of the house roof downpipes. I intend to create a swale downslope to stop the water running off too fast. At the moment, creeping thistle is trying to take over that area. The thistle is good for chop and drop biomass too, but comfrey would be less prickly to deal with!

This is the website I go to when I wonder about growing things. It may not be suitable for every growing zone, but it sure makes interesting reading backed by scientific findings and dispel many myths.
I am NOT affiliated in any way to this person's blog, videos or anything like that! I just like to share it because of its content.

Ela La Salle wrote:This is the website I go to when I wonder about growing things. It may not be suitable for every growing zone, but it sure makes interesting reading backed by scientific findings and dispel many myths.

Ela, the link didn't come through in the post.

You should never plant comfrey if you have too much green in your garden. The little flash of purple when it flowers is really insufficient at breaking up the overwhelming abundance of green. While not the best image, in such conditions you may want to try a variegated comfrey like this.

Jane Mulberry wrote:

Ela La Salle wrote:This is the website I go to when I wonder about growing things. It may not be suitable for every growing zone, but it sure makes interesting reading backed by scientific findings and dispel many myths.

Ela, the link didn't come through in the post.

Ups, sorry, I forgot to paste the link, so here it is.

https://www.gardenmyths.com/comfrey-dynamic-accumulator/

I read the article @ the link. How disappointing to learn that comfrey is not what it's touted to be. How can so many have been so ignorant that this is the first I've heard that it doesn't work the way so many have described?

Fortunately,  there does still remain the mass it produces,  and the medicinal properties it carries.  So I'll have to revisit whether it makes for good animal feed.

I did my permaculture design course with the late great Patrick Whitefield, at Raglans Lane Farm in Gloucestershire UK….. a permaculture training site as well as an apple / apple juice producer.
They had rows of apple trees under planted with comfrey…. which were performing better than those with
grass underneath.
The comfrey was a complete ground cover under and around the trunk perhaps with approx 1metre diameter cover from the trunk.
Explanations given were that the comfreys deep tap root did not interfere with the apple trees shallower root system, that it brought up deeper minerals than the apple tree had access to, that it out-competed the grass which was more competitive in terms of shallow roots, and that the option to cut and drop on site providing a very rich plant fertiliser. Also good bee attractor and possibly other beneficial insects.
I have been planting comfrey under apple trees since my PDC and at the moment see no reason to stop
Great medicine and food also for us humans

Ela La Salle wrote:This is the website I go to when I wonder about growing things. It may not be suitable for every growing zone, but it sure makes interesting reading backed by scientific findings and dispel many myths.

We have plants on our land which many people would be happy to plant, but in my ecosystem, they easily take over and out-compete other useful species.

The blog you linked to said this:

Dynamic Accumulators – Do They Exist? If we use the common definition for dynamic accumulator all plants would qualify. In my previous post I refined the definition to the following:
A dynamic accumulator is a plant that will absorb and retain, in the leaf, at least one nutrient at levels that are at least 10 times higher than the average plant.

However 3 of the example alternative "organic fertilizers" the author mentioned were "meal" - which is generally ground up seeds with something else removed for some other purpose which may concentrate what is left. I think I would expect seeds to have more concentrated NPK than most leaves, because it has to have the concentrated goodies to support enough root and leaf production to hatch a plant.

The blog also said:

One thing it does do is produce a lot of leaves quickly...  Harvesting and composting comfrey also adds extra work. Is it worth it?

This is certainly true in the spring in my ecosystem. It seems to take good advantage of the moisture left in the soil from our we winters. I rarely transfer those leaves to my compost, but chop and drop in place or near-by. However, I've noticed how important the moisture content of "greens" in my compost are. It makes me wonder whether dropping comfrey leaves around the trees where it's planted might actually add moisture to the ecosystem rather than just conserving moisture. It also seems to me that for the plants to produce so many leaves in the spring, that like our Big Leaf maple trees, their roots must be holding onto a lot of nutrients during our wet winters that could otherwise be leaching away. I've heard that spring bulbs may have that affect in forests.

Ultimately, labels can be a problem, rather than a help. In my ecosystem, a tree that was struggling for several reasons, seems to be happier with the comfrey around part of its shadow. I tried Seaberry, but it died either due to deer browse or too much shade. I can't say if the tree is happier because of the rocks I removed to plant the comfrey, or the punky wood I added at the same time. At the moment, it seems to be the "right place at the right time" for this plant, but I am well aware that there could be many "wrong places or wrong times". That's why I sometimes find it difficult to just get out there and try things - nothing comes with guarantees!

Deedee Dezso wrote:I read the article @ the link. How disappointing to learn that comfrey is not what it's touted to be. How can so many have been so ignorant that this is the first I've heard that it doesn't work the way so many have described?

Fortunately,  there does still remain the mass it produces,  and the medicinal properties it carries.  So I'll have to revisit whether it makes for good animal feed.

Well...as I mentioned, it makes interesting read. There are more interesting articles and YT videos. I don't know about feed for animals as I don't have any (by-law rules). I am an average gardener that hungers for knowledge in growing sustainable foods on what little land I have, in a frugal and the best way I continue to learn, through permies and that blog.

Jay Angler wrote:

Ela La Salle wrote:This is the website I go to when I wonder about growing things. It may not be suitable for every growing zone, but it sure makes interesting reading backed by scientific findings and dispel many myths.

We have plants on our land which many people would be happy to plant, but in my ecosystem, they easily take over and out-compete other useful species.

The blog you linked to said this:

Dynamic Accumulators – Do They Exist? If we use the common definition for dynamic accumulator all plants would qualify. In my previous post I refined the definition to the following:
A dynamic accumulator is a plant that will absorb and retain, in the leaf, at least one nutrient at levels that are at least 10 times higher than the average plant.

However 3 of the example alternative "organic fertilizers" the author mentioned were "meal" - which is generally ground up seeds with something else removed for some other purpose which may concentrate what is left. I think I would expect seeds to have more concentrated NPK than most leaves, because it has to have the concentrated goodies to support enough root and leaf production to hatch a plant.

The blog also said:

One thing it does do is produce a lot of leaves quickly...  Harvesting and composting comfrey also adds extra work. Is it worth it?

This is certainly true in the spring in my ecosystem. It seems to take good advantage of the moisture left in the soil from our we winters. I rarely transfer those leaves to my compost, but chop and drop in place or near-by. However, I've noticed how important the moisture content of "greens" in my compost are. It makes me wonder whether dropping comfrey leaves around the trees where it's planted might actually add moisture to the ecosystem rather than just conserving moisture. It also seems to me that for the plants to produce so many leaves in the spring, that like our Big Leaf maple trees, their roots must be holding onto a lot of nutrients during our wet winters that could otherwise be leaching away. I've heard that spring bulbs may have that affect in forests.

Ultimately, labels can be a problem, rather than a help. In my ecosystem, a tree that was struggling for several reasons, seems to be happier with the comfrey around part of its shadow. I tried Seaberry, but it died either due to deer browse or too much shade. I can't say if the tree is happier because of the rocks I removed to plant the comfrey, or the punky wood I added at the same time. At the moment, it seems to be the "right place at the right time" for this plant, but I am well aware that there could be many "wrong places or wrong times". That's why I sometimes find it difficult to just get out there and try things - nothing comes with guarantees!

Last year I planted lots of comfrey (believing myth) and this year I have only one single plant.
I also love rocks. I gathered many for a long time, which I placed around black currant and gooseberry bushes, only to discover that rocks hold the heat and eventually were "cooking" the roots.  So, no more rocks unless I want a rock garden with succulents.
It could be, that your tree's roots got too hot and dried out quicker, so the tree struggled.
One can argue that it wasn't comfrey shading roots, but heat from rocks .
Punky wood is a funny too, in a way, that it usually works in a setting where it actually belongs (forest, swamps...?)

(My productive, carefully and lovingly tended raised beds were hijacked last year after we had poplar tree removed in Spring.  Everything I planted did poorly. The roots sprag in places by the hundreds! I talked about it in another tread.
Needless to say, one can have healthy, beautiful soil/plants,  that can be destroyed  by one mishap). Ugh!

Ela La Salle wrote: (My productive, carefully and lovingly tended raised beds were hijacked last year after we had poplar tree removed in Spring.  Everything I planted did poorly. The roots sprag in places by the hundreds! I talked about it in another tread.
Needless to say, one can have healthy, beautiful soil/plants,  that can be destroyed  by one mishap). Ugh!

I hear you - there are trees that do that! I guess that's where humans learned the concept of coppicing from!
I had Big Leave Maple roots I put in a bed that I would have thought were thoroughly dead... not... however, I just kept pulling the suckers up as fast as I saw them, and solved the problem. If only that approached worked with Himalayan blackberry roots. They are the worst I've run into so far.

Not sure where you are located. The rocks I referred to were underground, so I don't think they would have added heat, but more decreased water in the soil and the ability of the tree to send roots in a direction they needed to go.

However, I am trying flat rocks around my tomatoes this year. We don't get hot weather and in particular, our nights cool off a lot, so I'm actually trying to capture daytime heat. One's ecosystem is critical to which tools in our tool-box we choose to use.

i stopped planting comfrey and now are dividing and spreading my Canada red rhubarb. still gives plenty of green with 30in. wide leaves but also gives food and never spreads. i cut off the immature seed stalks so they don't bolt. i give them some composted manure every couple years and they are extremely productive. been selling my extra at farmers markets and i sell out quickly.

Joylynn Hardesty wrote:In my region, don't plant Comfrey in your driest spot. That plant is barely alive, dying back during our seasonal drought, waiting until spring to try again. Don't plant in full shade. They die. Plants in 6 hours of sun are more than twice the size of plants in 4 hours of sun.

Die back as in "will regrow when moisture is available" or as in "dead and will rot  when moisture becomes available"?

Well, I'm not positive. For about 5 years in that dry spot, it would come back in early March for spring, wither to the ground in July, sometimes coming back in September with the rain, and die to the ground in late December. Up again in March. That's pretty hard on a plant. While I had planned on transplanting it, I do not remember doing so, and there is no comfrey in that spot this year. I think it was finally exhausted to death.

The happiest that poor plant ever looked was about like this one that I started from a root cutting this April.



In comparison, These plants were chopped back, root cuttings taken from them, and they are ready to be harvested again.



And here is a plant that has not been harvested this year yet.



I will not be planting comfrey in that spot ever again.