comfrey plant

Garden Comfrey (Symphytum Officinale) is a medium sized perennial herb growing to 30-900cm. It has a hollow stem and large ovate leaves covered with coarse hairs, to which some people are sensitive! The small bell like flowers which grow in pairs are loved by bees and come in a range of colours from deep purple to white. It prefers a moist shady position and is often found in damp low-lying places in the wild near ditches and drains. It will grow anywhere and can be invasive. Stocks can be increased by dividing the plants in Autumn or taking root cuttings in Spring. Most gardeners will already be familiar with the use of the leaves as a fertiliser, but it is as medicinal herb that its best known. The leaf contains a protein called allantoin which encourages cell division and is responsible for many of its healing properties. As its common name "Knitbone" implies, it produces amazing results in speeding up the healing of sprains and broken bones. Ulcers and other similar skin conditions such as sores and damaged tissue respond well to a mash of the leaves or root in the form of a warm poultice. Comfrey oil will ease aching joints, strains and rough skin, all occupational hazards to the gardener. Its easy to make, take a large dark airtight glass jar and pack it tightly with Comfrey leaves, which have been cut in to pieces about an inch long. Label and date and put the jar into a dark place and leave for 18 months to two years. The leaves will slowly decompose to make a dark amber/green emulsion, halfway between an oil and a liquid. Mixed with a little moisturizing lotion it is easier and more pleasant to apply. It can keep for many months. If you are sensitive to Comfrey and you would know very quickly if you were, wear gloves when you handle the plant.

After a hard day in the garden, soak in a healing herbal bath by placing fresh Comfrey leaves in a muslin bag and suspending this under a running tap. This really does relax muscles and ease aching joints. It is said to improve skin texture and give a more youthful appearance. It also contains calcium, potassium and phosphorous along with valuable vitamins such as A, C, and B12.

Ingestion of Comfrey is not advised as modern research points towards ingestion of Comfrey as responsible for Liver damage in humans.

 In the garden

 Comfrey is known as the "compost plant" because it contains more potash than farmyard manure. Many European farmers grow it to plough back into the soil to enrich the soil. If grown on a large scale, the first cutting should be made in October, thereafter every 6-8 weeks, which could give up to 5 cuttings a season.

 *Comfrey leaves are essential in the compost heap, breaking down quickly to release important minerals into the compost.

*Comfrey is also a compost activator - accelerating the decomposition of the compost heap.

*Fresh comfrey leaves can be picked and allowed to wilt for 2 days, and then can be spread on the ground under plants as a nourishing mulch.

*Fresh comfrey leaves can be soaked in water for 1 month to make a rich liquid fertiliser. This liquid manure is rich in potassium, calcium, phosphorus, Vit A, C and B12 and is very useful for the organic gardener. The plants which visibly benefit from comfrey fertiliser are tomatoes, potatoes, peppers of all types and cucumbers.

 There are two methods of converting the comfrey leaves into a liquid manure.

 (1) Fill a plastic or fibreglass drum or bucket roughly half-full of freshly cut leaves and cover to the top with water. (6 kg leaves to 90 litres water) Cover with a lid and allow to mature. Stir occasionally. Unfortunately this mixture stinks terribly because comfrey leaves contain 3.4 % protein, and it is this protein which stinks when it rots. After 3-4 weeks, pour off the liquid, strain and dilute 1 cup comfrey "tea" per litre of water. Pour this dilution over the roots of the plants.

 (2)     Drill a hole in the side just above the bottom of a plastic dustbin, or use a plastic drum with a tap at the bottom. Place this on a stand so that another container can be put below the hole. Pack the drum full of fresh comfrey leaves. Place something very heavy on top of the leaves - bricks, or a rock, a chunk of metal wrapped in plastic - which will squash the leaves down. Cover the drum with a lid. After 3 weeks a black liquid will start running out of the hole into the container. This is called a comfrey concentrate. Suggest that this contraption should be positioned under a shelter so that if it rains the concentrate will not be diluted with rainwater. It can be stored in a dark glass bottle and can be diluted 1:40 for a foliar food, (which can be sprayed on plants) or 1 tsp per 1 litre water for general plant food. There are smaller variations of this system which are suitable for the average gardener.

DO NOT USE a metal drum as it will rust and put toxic iron oxide into the liquid manure. 


*        Water regularly

*        Supply with a source of nitrogen. e.g organic compost or grass cuttings

*        Cut frequently once the plants are established



 New plants should not be harvested during their first year but don't forget to remove the flowerheads. (Comfrey should not be allowed to flower as it weakens the plant.) For established plants harvesting usually starts about October. The plants are ready for cutting when they are about 60cm high and cutting should continue regularly throughout the season up until April. During the winter months the leaves die back and all the nutrients are stored in the roots until the following spring.

Using your comfrey plants in the  garden

 * Wilted comfrey leaves can be placed in the bottom of potato trenches and in the planting holes of runner beans and tomatoes.

 *  They can be used as a compost activator. Use a thin layer of leaves in between other layers when making compost.

 * The leaves can be made into liquid fertiliser for pot plants, greenhouse crops and hanging baskets. Comfrey solution is very rich in potassium and is particularly recommended for tomatoes and peppers. Be warned it pongs!

 *   Use the leaves for mulching. Place a 2 " layer of comfrey around the plants. The comfrey mulch layer can also be covered with a layer of grass clippings.

 *  To make potting compost. Mix comfrey leaves into well-rotted leaf mould several months before you wish to use the potting compost.

 Fresh leaves:

*    Comfrey leaves and stems rot very easily and rapidly turn to a black yucky liquid.

*    Layers of comfrey can be placed on the compost heap from time to time to act as a compost accelerant.

*    Spread a layer in the sweat pea, potato or bean trench.

Alternatively, place the leaves in water and leave for a few weeks to decompose, use as a liquid fertiliser around the garden – NB it smells!

 A more concentrated form of comfrey can be obtained by placing the leaves in a container with a hole in the bottom and another waterproof container underneath.Compress the comfrey leaves with a brick or other heavy weight. Leave the leaves until the liquid (a black treacle) starts to drip out of the bottom into the second container. This is a less smelly method and the concentrate that drips from the bottom can be collected and stored over winter, then heavily diluted (15:1) to use on spring crops.