If you have never heard of Comfrey (Symphytum oficinale), then this article will explain why you should know about this plant if you are a gardener.
The long, tubular-shaped pink or purple flowers are absolutely adored by bees, wasps, butterflies, and pollinators. In the past, comfrey was eaten as food, often used as animal fodder, and also for medicinal usage.
Read on to discover why your garden should not be without a comfrey plant!.
Types of Comfrey
- 1 Types of Comfrey
- 2 Comfrey roots are very special
- 3 So why should you grow comfrey? 9 reasons.
- 4 What nutrients do comfrey leaves contain?
- 5 How to plant your comfrey root
- 6 How do I make new Comfrey plants?
- 7 Cutting comfrey leaves
- 8 How to Grow Comfrey from Seed
- 9 How safe is comfrey as food or medicine?
- 10 Modern-Day uses for Comfrey
Comfrey grows wild in the countryside all over Britain and there are over 40 different varieties in countries that stretch from the UK through Europe and as far away as Siberia.
- In the UK, it is sometimes known as English comfrey or common comfrey, to differentiate it from another similar plant known as Russian comfrey. There is another popular allotment variety called “Bocking 14” named after the village where this strain was developed.
- In the US, comfrey was introduced by a settler English family, and it now grows freely in USDA hardiness zones 4-9 in central and southern states.
- There are many wild versions of this plant, with slightly different appearances and all of them are related to the Borage plant, which has blue flowers.
Comfrey flowers tend to come in shades from a delicate creamy pink (UK common comfrey (Symphytum officinale) to a darker shade of lilac and even purple.
Both Russian comfrey (Symphytum x uplandicum) and the variety known as “Bocking 14” comfrey have purple, drooping flowers with white interiors. This last comfrey was developed by Lawrence D Hills and takes its name from Bocking, the UK village where pioneering work was undertaken on 21 varieties of comfrey in the 1950s. Neither of these plants can be grown from seed, so you will need to purchase some root to grow these types of comfrey in your garden.
Comfrey roots are very special
The reason why comfrey leaves are so rich in nutrients is due to the length of the root of a comfrey plant. It can grow as deep as 2 m (6.5 feet) into the ground and as it grows, it extracts minerals and nutrients, not available to many surface-rooting plants. These are transferred into its leafy green foliage and made available to animals who graze on them, or humans who pick them for use in agriculture. Using the leaves shares these deep nutrients sources with other, hungry shallow-rooted plants.
So why should you grow comfrey? 9 reasons.
- Comfrey leaves can provide home made fertilizer for fruiting plants (tomatoes, cucumbers, etc).
- You can cut the leaves 3-4 times per year to add to compost, the soil, or pots.
- You can allow a layer of leaves to decompose in large spaces. eg. a sweet corn patch where it will add nutrients over a long period.
- Bees love the flowers so you will attract many to fertilize all the plants in your growing space.
- It helps you to avoid chemical fertilizers.
- It improves soil pH over time.
- It is a great addition to potted plants.
- It is easy to divide to make new plants.
- It is free!
What nutrients do comfrey leaves contain?
When plants grow, you need to nourish the roots, the stem, the leaves, and the flowers and fruit if it occurs. Comfrey leaves, picked and submerged in a bucket of water, will release the following nutrients: potassium, magnesium, calcium, iron, and vitamin B12.
- Magnesium is essential for seeds to germinate. It is also required to make chlorophyll, the green pigment of plant leaves. Chlorophyll is needed to absorb enough sunlight to make food for the plant in a process called photosynthesis. Without magnesium, leaves begin to drop off your plant, and eventually, the whole plant may die off.
- Potassium is the K in NPK commercial feeds. It aids the plant to make food from sunlight through a process called photosynthesis.
- Phosphorus is important for growth, whether that is healthy roots or flower production, or the ability of the fruit to set and to make seeds. Phosphorus is an essential soil ingredient, often seen as the “health tonic” for vigorous growth. If there is enough in your soil, the plant will be able to withstand harsh winters and grow to its maximum height and spread. Without it, your plant will not reach its full size and the fruit may be smaller.
- Iron also helps the plant to make chlorophyll. Without iron, the leaves look pale.
- Without calcium, the whole plant dies off and the leaves begin to drop off the stem.
How to plant your comfrey root
It’s easier to plant comfrey from a root division or offset. See how to grow from seed below. Wear gloves because the leaves have tiny hairs which can irritate human skin.
- As soon as the spring sunshine warms the soil is the time to plant your comfrey root. Choose a sunny patch if possible and dig a trench at least as long as the root section and slightly deeper. Allow 8 cm (3 in) extra to cover with topsoil. Make sure you remove any large stones as the extensive roots will grow around these.
- Some gardeners like to cover this with a layer of straw and there are rumors that the best way to produce a fantastic comfrey plant from a new root is to water it with urine. I cannot vouch for this method but do let me know if it works for you!
- Comfrey tolerates most soils but it thrives in deep, fertile soil with plenty of organic content. The pH of the soil can be anywhere from 6.5 to 8 but experienced growers recommend a pH between 6 and 7.
- Cover the whole root with earth and water it immediately and every week in the first few months. Do not worry if no leaves show for a few weeks; the roots will be growing. This plant prefers deep soil in full sunlight to thrive but it will happily grow in shade for some part of the day.
- Although comfrey will tolerate some shade, the best foliage comes in a really sunny position and it is the leaves you need for other plants so give it a good position. It will take at least a year before it reaches its full size so do not pick leaves until it is well established.
- It is a perennial, hardy plant in the UK, so you can leave the root in a permanent position in the flower bed over the winter. It looks great in an established flower bed because it is in flower as long as the frost keeps away. Do place a marker of some sort though, because the whole plant dies back and surprises you again the following spring! It spreads quite widely too, so allow a 3 foot square for each plant to allow them to thrive
- I always leave the plant to die back naturally and remove any offsets and re-plant them. In my experience, comfrey roots need to be moved every 3 years, as comfrey takes so much from the soil where it grows. To help with this, you can companion plant with nitrogen-fixing plants like vetches, peas or clovers and move the position of the comfrey every 3-4 years.
How do I make new Comfrey plants?
You can grow common comfrey from seed (see more below) but not the other 2 types discussed. Root division is the answer!
All comfrey roots can simply be divided every 3-4 years to make new plants and then transplant these to a new situation. Do this in late Autumn or spring. Dig up the root as much as you can and then divide it into four sections. You can use a spade or even strong pruning saw to do this.
Cutting comfrey leaves
In its first year, allow the plant to develop and do not cut leaves until the flowers appear. This usually starts in mid-April and continues until the weather gets chilly in the autumn. Allow the bees to pollinate the flowers and enjoy the sound of humming bees. In June or July, you can pick just a few leaves but remember this is a perennial which will last a long time, so start cutting in earnest from its second year. Cut leaves from the base.
Make comfrey feed:
I’m not very scientific about quantities but my tomatoes have been thriving on this for years. I recommend picking a handful of comfrey leaves (just as the tomato flowers start to appear) and then I add these to a bucket of water.
You may need to shred the leaves a bit and then use something to weigh the leaves down. Allow them to stew for at least 5-6 days but you can leave this like a stew gently simmering all summer! You can keep adding leaves over a period of time but be warned!
The smell of comfrey feed is best kept far away from your back door. It is not perfumed but it is full of potassium which is fabulous for tomatoes, cucumbers, aubergines (eggplant), and squashes and will also help fruit to set and swell.
To use it, you need to dilute this mixture with water so fill up your watering can a quarter full with this mixture (wearing a peg on your nose) and top up with water. It’s not an exact science, but the darker the liquid, the more water you add.
A more precise measure is 1 part feed to 9 parts water. I rarely have measuring jugs at the allotment so I can vouch for my approximations as having no detrimental effect on my plants so far.
Make comfrey mulch:
Normally you can pick leaves as you need them, although some gardeners prefer to cut the whole plant back 2 or 3 times a year. Comfrey recovers quickly and grows more leaves. I prefer to grow several rows of comfrey so I just pick leaves from different plants as I need them.
Pick a bunch of leaves and add them directly to the ground as you plant. These leaves will retain moisture as a green layer, act as a decoy layer for slugs and snails and also decompose directly in the soil, making nutrients available for a long time for the growing plant.
Add a few leaves to pots as you re-pot plants:
If you have a plant that needs re-potting, then add some dried comfrey leaves to the mix. I usually pick leaves and allow them to dry in the sun, then crumble them into the potting mix and then replace the plant.
Add leaves to your compost bin:
Keep harvesting leaves all summer and add these as a green layer in your compost bin. If you have grass cuttings as well, these two will add bulk and nutrients to the compost bin.
How to Grow Comfrey from Seed
Russian comfrey will not grow from seeds so you must start from a piece of the root of the plant. Its flowers are really attractive but you will not get seeds from this plant. Bocking 14 must be grown from a root cutting or division.
Common comfrey seeds need to be kept cold for germination to occur and germination can be extremely slow. Actually, having sown seeds in a bed one year and given up due to the lack of germination, I was amazed when a row of comfrey suddenly appeared a year later after an especially cold winter.
Seeds remain viable for at least a couple of years so be patient! Once you have a healthy plant, you can remove offsets – this often happens by accident and replant them in a new location.
From seed, the only viable UK plants must be from common comfrey. Just place them in a pot of compost, and water and wait.
- Hardy Perennial (Returns Each Year) Suitable Zones 4 – 9
- Beneficial Plant with Many Uses; Composting, Breaks Compacted Soils, Fodder and Mulch
- Prefers Full Sun, Partial Shade. Great for Mulching and for Orchard Understory
- Non-GMO - Heirloom - Open Pollinated
- Seeds are for the current and following growing seasons. Growing instructions and plant Images are included on the seed envelope. Seeds are stored in environmental conditions that promote seed life (Dark/Dry/Cool).
- Easy to Grow: Comfrey is a hardy perennial that grows 36 to 60 inches tall and is easy to grow from seed.
- Planting Tips: Sow seeds in spring or fall. Soak seeds in water in the refrigerator for 48 hours or more, then sow seeds on warm potting soil at 68-75F and tamp down. Keep moist in mild warm light. Germination 10-30 days.
- Beneficial plants for a wide range of uses: compost, break up compacted soil, feed and mulch
- Likes full sun, partial shade.
- Non-GMO - Heirloom - Open Pollinated
How safe is comfrey as food or medicine?
Comfrey has been used for medicinal purposes and animal fodder all over the world from Europe to Arabia for hundreds of years. Comfrey is safe for animals and some like to graze on fresh comfrey, including pigs, sheep, chickens, and poultry.
However, if the leaves are picked and allowed to wilt slightly then rabbits, cows and horses also like to eat them. A clue to the use of comfrey in health can be seen in its many names.
The Latin word Symphytum can translate as uniting or growing together and the middle English comferi is probably based on the Latin word confervia, which not only means to heal but also means to boil (together), which could refer to the way that a cracked or broken bone could re-knit together.
Traditional medicine used to wrap comfrey leaves around broken bones, like a modern-day bandage, to speed healing. In the past, this plant was known as “knitbone” or “boneset”.
Historically, this plant was used by Pliny the Elder to make a healthy wine tonic and for wound healing. The Romans treated bronchial infections with comfrey, and it was used for wound healing as well as as a herb for cooking.
There are reports of its usage to help gum disease, bruises, arthritis, and gout. It has been used through the ages as food, an astringent, and an anti-inflammatory. In the Middle Ages throughout Europe, comfrey was eaten by humans in salads and the flowers were made into herb oil to soothe bruises However, in the 20th century, some researchers point to internal consumption of comfrey causing liver damage and tumours in experiments with rats.
Therefore in this article, my advice is to use comfrey only for external usage until further reports can verify this information and examines the history of medical usage, and advises some methods to use the plant externally.
Modern-Day uses for Comfrey
- First aid. It is known that the application of a poultice of compress leaves directly to any area where there is heavy bleeding is a fantastic way to stop the flow of blood. As emergency first aid, if you get cut on an allotment or out in the wild, comfrey is useful to recognize. Pick some leaves and wipe away the prickly surface, then just wrap it around the wound to stop bleeding. It can be tied with grass or string or anything available.
- Shoe insoles. The thick leaves offer some blister protection if you are walking and need some padding! Just pick a few leaves and place them strategically between your socks and the shoe to ease blisters.
- As a moisturiser. The leaves feel very thick and if you tear one open, you can see the moisture contained within the leaves. Traditionally, this was processed into an ointment or salve and applied to bruises, painful arthritis conditions, varicose veins, and gout. Nowadays, some doctors do not advise the direct application to the skin in case of absorption of toxic substances.