Comfrey

Symphytum officinale

Comfrey is one of the most useful plants to organic gardeners, and plays an important role in any sustainable permaculture garden.

It is a perennial herb of the family Boraginaceae with a black, turnip-like root and large, hairy broad leaves. When it flowers it bears small bell-shaped white, cream, purple or pink flowers which are extremely attractive to bees, and make an excellent bee forage. It is native to Europe, growing in damp, grassy places, and this is a guide to planting it in a permaculture garden... somewhere damp is definitely recommended.

If comfrey has a ‘problem’ it is probably that it is just a little too vigorous a grower, and thus demonstrates the benefits of a good garden plan. Do not plant comfrey where you might want to move it later on... doing so is almost impossible! The plant will regrow from the smallest piece of root left in soil. If you do need to move/eradicate comfrey then try cutting down the leaves, and covering with several thick layers of newspaper, followed by a good thick layer of mulch. After several months this should cause the plants to just rot in the soil leaving behind rich, black compost.

Another ‘problem’ to look out for is self-seeding comfrey. Try to avoid this by removing the flower heads as soon as they finish flowering and prior to them setting seed. Alternatively, try growing the ‘Bocking 14’ variety which was developed at the Henry Doubleday Research Association in the 1950’s. Bocking 14 is sterile, and therefore will not set seed (one of its advantages over other cultivars as it will not spread out of control), thus is propagated from root cuttings.

The best way to propagate comfrey is via root cuttings, pieces approx 3cm long will root readily in moist soil, or by producing offsets by driving a spade horizontally through the leaf clumps about 3 inches below the soil surface on strongly growing plants. The original plant will quickly recover, and each piece can be replanted with the growing points just below the soil surface, and will quickly grow into new plants. The following video demonstrates one method for propagating comfrey.

Uses of comfrey in the permaculture garden are many, and varied, but some ideas are;

Compost Activator – Comfrey is a very deep rooted plant which allows it to access and accumulate minerals that wouldn’t be freely available to other plant species. As a result, and due to its high nitrogen content, comfrey will speed the ‘heating’ of any compost heap significantly. Comfrey should not be added in quantity as it will quickly break down into a dark sludgy liquid that needs to be balanced with more fiborous, carbon rich material.

Liquid fertiliser- As noted above, comfrey is an excellent mineral accumulator, and these minerals can be quickly accessed by making a ‘comfrey tea’. The tea can be produced by either rotting leaves down in rainwater for 4-5 weeks, or by stacking dry leaves under a weight in a container with a hole in the base. When the leaves decompose a thick black comfrey concentrate is collected. The original method can be used undiluted or dilute 2:1 for sensitive plants and seedlings, but the sludge collected by the latter method MUST be diluted at 10-20:1 before use. Don’t brew this tea too close to the house as the resultant ‘goodness’ can become a little wiffey!

Livestock Forage – Comfrey is excellent forage for livestock and is readily eaten by poultry, cattle, rabbits, sheep, pigs and horses. It is also an excellent bee forage. Just be aware that comfrey does contain some hepatotoxic pyrrolizidine alkaloids which have been shown to cause cancer when ingested in large quantities. These alkaloids don’t seem to come through the nectar, meaning honey is safe, but when feeding plants to livestock don’t give them too much. Think of it as a ‘super-food’ and you won’t go too wrong.

Potting mixture – Comfrey forms a great leaf mold potting mix. Two year old, well decayed leaf mold should be used, this will absorb the nutrient-rich liquid released by the decaying comfrey.

Nutrient/Water Trap – Comfrey grows very rapidly, and likes nice damp conditions. We can take advantage of this fact by planting comfrey downhill from any nutrient source (eg, chicken run or livestock sheds) and using it to naturally mop-up any nutrients that would otherwise be lost from these sources. Doing this improves the fertility of your ‘patch’ but also prevents detrimental impacts on other areas such as the eutrophication of natural waterways.

Medicinal – Comfrey is one of the most valued herbs of the western herbal tradition. In fact, the Great Culpepper in his ‘Modern’ Herbal wrote;

“the great comfrey helpeth those that spit blood, or make a bloody urine: the root boiled in water or wine, and the decoction drunk, helpeth all inward hurts, bruises, and wounds, and the ulcers of the lungs, causing the phlegm that oppresseth them to be easily spit forth; it stayeth the defluxions of rheum from the head upon the lungs, the fluxes of blood or humours by the belly, women's immoderate courses, as well the reds as the whites; and the running of the reins, happening by what cause soever.”

Note: The hepatotoxic pyrrolizidine alkaloids mentioned earlier have caused this herb to be listed on the poisons schedule in Australia, and it’s internal use is limited. For more information on this use see a qualified medicinal herbalist.

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