Growing Comfrey for Added Garden Fertility

Growing comfrey makes sense for many gardeners as it is such a good source of fertility.

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The question is not so much “How to grow comfrey?” as it is how to stop comfrey from growing everywhere!

Growing comfrey is rather easy if you have any spare space in your garden. Ideally, you need to be given a chunk of comfrey to plant directly into the soil. Friends who already have comfrey growing in their garden could be persuaded to part with a small piece of root. Failing that, you can buy comfrey in most garden centres which sell herbs.

Make sure that the comfrey is planted deeply enough to bury the roots and water it well. Ensure that it stays well watered for a few days while it gets established.

Comfrey likes free-draining, loamy soil but is not especially fussy. If you have a very hard sub-soil you may need to break it up with a spade for best results.

Comfrey - the invader!

Once it is established it will happily romp around your garden unless you take steps to stop it. The roots will develop spurs which can be broken off to form new plants. It will also readily seed and new plants can appear yards away from the parent plant, at the other side of the garden, even.

The moral is – be careful where you plant comfrey! It is an incredibly useful plant but it is also a space invader which will push other plants out of the way. Comfrey is a garden thug, like mint. It can propagate itself with amazing success and appear, triffid like in your borders and beds.

There is a variety available known as “Bocking 14” which was developed by the Henry Doubleday Research Association. It does not tend to spread so readily, so may be a good choice if you want to be sure of avoiding self-propagation.

Young plants are quite easy to uproot before they have become too big. Older plants will need some spade work to get them out.

Growing comfrey in a bed

If you want to plant a bed of comfrey plants, give young plants between two to three feet space between each. Incorporate some good quality manure or compost in the bed for a fast start. A damp and remote part of the garden is a good choice. Comfrey plants like plenty of moisture and sunny conditions or half shade.

Growing comfrey in very small gardens is perhaps best avoided - unless you really like it! Comfrey plants can grow very tall and crowd out lesser plants. You may need to hack them back just so that other plants get a chance.

A highly useful plant!

The good news is that comfrey is a plant of incredible utility. It has such deep tap roots that it is able to bring up nutrients from far down in the sub-soil. Many people grow comfrey this reason alone. It gradually will help you to build up your garden's fertility. Comfrey is rich in potassium and nitrogen.

Cutting comfrey can be done with a garden sickle or any sharp blade. Wear gloves if you can because the leaves are hairy and slightly prickly and may cause some skin irritation. You can cut growing comfrey at almost any time once it is established. Cut small amounts or cut the whole plant down to almost ground level. It will usually bounce back again in no time.

Comfrey tea

You can cut comfrey down several times in a season and use the leaves to make comfrey tea, or liquid fertiliser. There are several ways of making comfrey tea for your garden. Cut the leaves before flowering and drown them in a bucket or tub of water. After a few weeks the leaves will have fermented and broken down and you can drain off the liquid to use as fertiliser. You should dilute it well before applying it to plants. You can do a similar process without any water – in which case you end up with a thick, dark liquid which needs diluting lots before use. Place the leaves in a waterproof bag or tub and cover them with a lid. Leave for 5 to 8 weeks to decay. Pour off the (smelly) liquid and use it sparingly to add to the watering can as a liquid feed.

You can also add the chopped up leaves to the soil where you are planting potatoes or beans. This will get your crop off to a good start.

You can add comfrey to your compost heap, where it will act as an activator, tending to help the heap to heat up. Don't add a large amount in one layer as it will decay to a slimy mess which will then slow down decomposition of the heap. Rather, add it chopped in with other ingredients.

To avoid the risk of depleting your comfrey plants, it is best to leave them to their own devices later in the year. In autumn the nutrients in the leaves will drain back into the root system to help the plant survive the winter. You may not even be able to see any evidence of the plant in the winter months. In spring it will soon bounce back and come into full vigorous growth.

Can you eat comfrey?

It is not really advisable to eat comfrey. It contains a toxin which can damage the liver. There have been calls to ban comfrey tea from herbalist's shelves because of the danger of liver damage. I have cooked up small amounts and eaten them (it was OK) but, as the plant is mucilaginous and rather hairy, I don't think anyone is going to miss it too much as a spring vegetable.

You can certainly use it in animal feed. Hens are partial to it and I have nor heard of any problems with its use this way.

Comfrey has a notable place in herbalism and homoeopathy. It is regarded as an excellent aid to healing of wounds and broken bones.