HOW TO GROW COMFREY

How to grow comfrey

For any gardener who wishes to grow their plants by using strict organic principles, modern fertilisers can often be a bit of a sticking point. However, help is at hand from the native European herb Comfrey – otherwise known as ‘Knitbone’ as it was once used as a traditional remedy to help heal broken bones.

Comfrey has a naturally deep rooted and extensive root system and acts as a dynamic accumulator by extracting a wide range of nutrients from deep within the soil. These nutrients naturally accumulate within its fast growing leaves - up to 4-5 lbs per plant when cut.

How to grow comfrey

Because comfrey leaves lack fibrous tissue they can quickly break down returning their nutrients to the soil surface making them more readily available to cultivated plants. In addition there is little risk of nitrogen being ‘locked up’ during decomposition when comfrey is dug into the soil as the carbon to nitrogen ratio of the leaves is lower than that of a well-rotted compost. Comfrey is also an excellent source of potassium - an essential plant nutrient needed for flower, seed and fruit production. In fact comfrey leaves contain 2-3 times more potassium than most farmyard manures.

To begin growing your own comfrey you are best off using the cultivar known as ‘Bocking 14’, a special strain which was developed during the 1950s by Lawrence D Hills - the founder of the Henry Doubleday Research Association. Bocking 14 is sterile, and therefore will not set seed (an advantage over other cultivars as it will not spread out of control). Because of its sterility, this cultivar is normally propagated from root cuttings of offsets from the parent plant.

To produce your own ‘offsets’, it is best to choose mature, strong healthy specimens with no signs of disease - such as rust or mildew - to act as the parent plants. Drive a spade horizontally through the leaf clumps about 3 inches below the soil surface. This will remove the crown, which can then be split into pieces. The original plant will quickly recover, and each new offset can be replanted with the growing points just below the soil surface. Once established these offsets will quickly grow into new plants.

TIP. When dividing comfrey plants, take care not to spread root fragments around, or dispose of them on a compost heap. Each piece can easily re-root, and comfrey can be a very difficult plant to get rid of.

Comfrey will prefer to be planted in full sun although it will tolerate partial to near full shade. It is not so keen on thin, chalky soils, but you can give it a helping hand by dig deeply to break up the subsoil. Light sandy soils will benefit from organic matter, and being a fleshy plant it will require a decent amount of watering.

Comfrey will grow very densely and can be difficult to weed, so before planting, dig the soil over and remove any perennial weed roots. Luckily, it will tend to shade out most weeds once established. To get your comfrey off to a good start it is also well worth adding well-rotted farm manure or garden compost before planting – just fork it into the top 6 inches of the soil.

Do not cut in the first year, but once established you can harvest the foliage four to five times a season. Harvest by cutting the plant down to about 2 inches once the plants has reached at least 2 ft in height.

For related articles click onto the following links:
HOW TO GROW CHAMOMILE
HOW TO GROW COMFREY
HOW TO GROW LEMONGRASS
HOW TO MAKE LIQUID FERTILIZER FROM COMFREY

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