Saturday, 3 December 2016

Comfrey - the "Emperor's New Clothes" of plants

Remember the story by Hans Christian Anderson about the two weavers who promise to make the Emperor a set of clothes that is exquisite to intelligent people but invisible to anyone who is stupid or ignorant.  The Emperor and pretty much everyone claimed that they could see this amazing garment, all the while the Emperor paraded around in nothing but his under garments.  Well, comfrey is to farmers what these invisible clothes were to the Emperor.

I know I am going to get frowned upon by many permaculturists, but it has to be said, comfrey just isn't all that great.  There is a lot of hype about comfrey, I have heard glowing reports of it my entire life.  I have grown comfrey on and off in many different situations for many different reasons for most of my life.  I have spoken to a bunch of other people who have grown it and they have all experienced similar things to myself.  I have also done some research on comfrey to see how well it actually stacks up.  

Lets begin by looking at some of the claims about the benefits of this plant to a permaculture or biodynamic garden and I will try to briefly explain my experiences.
Comfrey struggling in the heat and about to be over run by grass
11 amazing reasons why people grow comfrey, but probably shouldn't

Wonderful mulch material – while it is true that comfrey makes an acceptable mulch there are many better alternatives for mulch than comfrey.  Many plants produce more mulch material which is just as high if not higher in nutrients, but is easier to handle.  Some break down faster, others slower, but none of them have the irritating hairs that comfrey has on its leaves.  I dislike those hairs, they are the main reason I decided to try and see if any other plants could be used instead of comfrey.

Compost activator and general ingredient – again, far better alternatives exist both in terms of bulk as well as the ‘compost activator’ status.  Where I used to live comfrey does not produce much bulk at all even when watered, it was simply too dry and hot for comfrey to cope.  I have seen comfrey grow on the south coast where the climate is mild and lovely, again it did not produce very much bulk.  As far as compost activation goes I am hard pressed to find anything that works as well as dandelions.

Mineral and micro nutrient accumulator and fertilizer – very little research has been done on this unfortunately and the research that has been done indicates that comfrey is actually terribly bad at this task.  I have a feeling that dandelion is better at this than comfrey as it has higher levels of most nutrients.  Plants such as horseradish, sorrel and turnip all have me wondering if they are better at this than comfrey as they all have deep roots and grow so fast but I have found no unbiased data to confirm or deny this hunch.

Deep roots help break up compacted soil – comfrey has deep roots, but from a lot of experience I can honestly say that these roots have never broken up compacted soil effectively or efficiently in any of the gardens in which I have grown it.  Other plants such as horseradish, dandelion, sorrel, daikon, turnip all can have extremely long roots and lack the irritating hairs of comfrey.  I think this whole “breaks compacted soil” thing can be better attributed to improving the soil biota than deep roots.  All of the other plants listed increase soil biota and appear to decrease soil compaction in my garden far better than comfrey.

Comfrey tea as a foliar fertilizer – I do honestly wonder if sorrel would be better at this, but I have never heard of anyone doing a trial of the two to see which is better.  Sorrel, dandelion, horseradish and turnip all contain high levels of nutrients, have deep tap roots, accumulate minerals from subsoil, produce copious amounts of green material etc so could potentially be used for this purpose.  It would be nice if one of those permaculture research places put some effort into confirming or denying some of this.  Unfortunately they appear to be too taken with confrey's hype to look further into it.

Livestock feed – in my experience very few animals will eat comfrey unless it has been wilted and none of them will touch it if it has been over wilted.  I don’t want a plant like this where I have such a fine line to walk, I have to do extra work to wilt it but if I wilt too much the animals may not even touch the stuff.  Our chickens, guineafowl, sheep, alpacas, cattle, and guinea pigs were all extremely reluctant to ever eat comfrey unless they had nothing else green to eat.  That's right, I have tried to feed it to many different animals many times.  Occasionally muscovy ducks would eat the comfrey plants to the ground, then they will not touch it again for months.  People often go on and on about how great an animal feed comfrey is, and on paper it sounds remarkable, but if I can not convince the animals to actually ingest it then it is pretty useless for this purpose.  If I was making pelleted feed I assume that comfrey would be a good ingredient, but I don't make pellets, I feed plants as they are.

Slug trap – surely there are better ways to control slugs than attracting them to live under leaves with irritating hairs.  I have only tried to collect the slugs under comfrey once, after getting covered by these hairs I decided to run the ducks in the yard instead.

Water cleanser (when growing in standing water) – comfrey is poorly suited to this as far as I can tell.  I have tried it twice and it has failed miserably both times as the plants rotted and died fast.  Many other plants are far better suited to this purpose.  Duck weed, azolla, QLD arrowroot, water chestnuts, duck potato, water cress, water celery, Vietnamese coriander and many others seem to out perform comfrey in this task.

Poultices and other medicinal uses – assuming that it works (which I think it does) and assuming it is safe then comfrey is reputedly great for these purposes, I am yet to find any substitutable plant.  This is actually the only reason why I would consider to grow comfrey again.

Nutrient trap at the bottom of a slope – comfrey is probably good for this if it is not too dry or too wet, but then I have to cut and carry the leaves which irritate my skin.  Many other plants are far better suited to this, QLD arrowroot is rather tall and is often used for this purpose, I can cut it easily, carry it easily, use it as mulch or compost and my animals actually ate it.  Sorrel out grew comfrey on my old property, lacks the irritating hairs, tastes nice, is hardier with heat/cold/dry/wet, and is actively growing all year, so I much prefer sorrel.

Grass barrier – I am yet to see this actually work with any plant, anywhere, ever.  Many people love to make this claim with comfrey and a few other plants but I will believe it when I see it.  I have seen running grasses such as kikuyu easily cross a large established comfrey barrier on a few different properties, they didn’t appear to even slow down at all.  Most of the time I try to weed comfrey to give it an advantage, yet it still fails at this task.  That being said I do not know any other plant that achieves this purpose better, perhaps the concept of a plant used as a grass barrier is a pipe dream?

Comfrey patch not really thriving despite being watered each day
After growing several varieties of comfrey (including the famous and well hyped Bocking 14) and have it never live up to its reputation so many times over so many years in several different climates, and seeing that there are better alternatives for almost every use, I have started to wonder why people grow the stuff.  The only reasons I can come up with are they grow it due to wishful thinking (similar to a placebo effect) or for some nostalgic reason.  I used to grow it for the medicinal qualities but did not bring any with us when we moved to town and don't plan to get any more now that I have moved again and settled.

I find that comfrey dies off completely during dry years if not watered, not just dies down but needs to be replaced as it does not return the following years.  Perhaps in climates less dry this is not the case, but I have lost most of my clumps the last two years of living at our property due to not watering them enough.  That's right, I watered them, just not enough water to keep them alive.  I also find that if it is too wet for too long it tends to rot and again die off completely and need replacement.  
Sorrel surviving the heat better than comfrey
In my property there were several established clumps of comfrey which I divided when we moved there.  Most of those died off completely in the few years we lived there and I tried to plant comfrey in places where they were more sheltered and easier to water.  I also had a small clump which appeared to be a slightly different type that a friend gave us, I had to nurture this each year otherwise I fear it would also die off completely just like the established clumps that were already there did.

Comfrey research
As well as the anecdotal evidence above (ie years of personal experience in several different climates) I have also done a little research on comfrey to compare it to turnip.  As you can see, turnips were much more consistent than comfrey.  While better results for comfrey were obtained in ideal conditions, worse results were obtained for comfrey in less than perfect conditions.  I have to note that my property does not have ideal conditions.  I need plants that perform well for me consistently under harsh conditions.

Use as a dietary supplements for people 
According to the research 85g of dried turnip leaves, in comparison to 567g of dried comfrey, supply adults with the total daily requirement of all essential amino acids, except for methionine.  That is a huge difference!  Eating half a kilogram of dried comfrey is possibly going to be bad for you due to the amount of pyrrolizidine alkaloids you would also be consuming.

Turnip - above-ground parts normally contain 20 to 25% crude protein, 65 to 80% in vitro digestible dry matter, about 20% neutral detergent fiber and about 23% acid detergent fiber . The roots contain 10 to 14% crude protein and 80 to 85%
in vitro digestible dry matter.
Comfrey – above ground parts contain 13 to 31% protein.  Comfrey was found in one study to be high in crude protein (21 to 31%), which increased from the first to last harvest. Research trials conducted by USDA scientists found crude protein contents only ranged from 13 to 17% for comfrey.

As far as protein goes I would choose turnips as they have consistently high protein.  Comfrey may have higher protein at some stages, but how am I as a home gardener *without access to a food lab) to determine when that is?

Turnip - 3 to 4 tons of dry matter/acre when harvested or grazed about 90 days after planting. Up to 1,000 grazing days/acre for 900 lb steers and 2,300 grazing days/acre for 90 lb lambs.  These are pretty decent statistics.

Comfrey – extremely variable 1.7 to 10.7 tons of dry matter/acre depending on the country tested.

As far as yield goes I would again choose turnips.  Comfrey can out perform turnips in specific situations but it performs poorly here.  I want to grow something that provides reasonable yields even under adverse conditions in bad years, not just when it is pampered or if I happen to grow it in its perfect climate.

Negatives of each plant
Turnip - The high levels of glucosinolates (which can cause thyroid enlargement in young growing sheep and cattle) can be a problem if turnip forage is fed for long enough.  Glucosinolates are higher in older forage compared to younger forage.  Slashing it seems to bring on a flush of new growth which makes it simple to avoid this problem.

Livestock should not feed on turnip during the breeding season or after the plants have begun to flower. Nitrate nitrogen toxicity can be a problem, especially if ruminants are allowed to graze on immature crops or if soil nitrogen levels are high.  The risk may remain for a longer period of time in autumn than in summer. Dairy cows should not be fed more than 50 lb turnip/head/day and should not be milked immediately after feeding on turnip to avoid milk tainting.  Cattle have reportedly choked on large turnips when fed the whole plant.

Turnip is also not perennial, so there is the added hassle of growing from seed time and time again.

Comfrey Extremely low palatability, irritating hairs which I hate, potential health risks due to pyrrolizidine alkaloids if consumed in large quantity or over a long period of time (although I think that the actual risk of this is very low).  The leaves die off over winter, wet soil seems to rot and kill the plant, and the plant does NOT like hot dry weather.

Should you grow comfrey
Sure, go for it, you have little to lose by trying.  You may be in its perfect climate and it may produce well for you.  Just don't be surprised if it happens to fall short of the hype.

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