Comfrey Plant: Benefits of Comfrey Root, How To Plant and Care for Comfrey

For example, in the country of Mexico, Comfrey plant has been used to treat rheumatism, while in Lithuania, its primary use has been in the treatment of bone and joint pain. In other countries, Comfrey is used to treat hepatic disorders, ulcers, gout, and other problems.³⁶

This section provides a near comprehensive list of the historical uses of the Comfrey plant in various areas.^{1, 27, 35}

1. Herbal Medicine

• Abrasions
• Arthritis
• Back pain
• Bone fractures
• Bruises
• Burns
• Colitis
• Diarrhea
• Gastritis
• Gout
• Joint inflammation
• Muscle pain
• Osteoarthritis
• Rheumatism
• Skin issues
• Sprains
• Ulcers

2. Food Crop

• Leaves tossed in salad
• Leaves brewed in tea
• Root dried and ground and drank as a coffee substitute
• Leaves (fresh or wilted) used as animal fodder

3. Fertilizer

Comfrey leaves and plant parts may be:

• Added to compost
• Steeped to make a liquid fertilizer
• Used as mulch
• Dried and ground into a powder fertilizer

4. Ornamental

• Grown as ground cover

5. Pollinator Gardens

• To attract different types of bees and insects

6. Pest Control

• Comfrey solutions may prevent powdery mildew
• Comfrey attracts predator insects which prey on insect pests

The contemporary use of Comfrey plant is more limited, as research has brought safety of use into question.

Understanding Comfrey Benefits

The Comfrey plant has various active compounds that have demonstrated health benefits. The allantoin and phenolic acids are mainly responsible for Comfrey benefits.

Allantoin is the compound which encourages cell division and promotes healing. Phenolic acids such as rosmarinic acid, among others, are noted for their antioxidant properties.³⁶

Some herbalists apply fresh leaves as a poultice to bruises and achy joints to obtain anti-inflammatory Comfrey leaf benefits. Leaf extract may even protect against skin photoaging.

If using this method, it is advised not to apply leaves directly onto open wounds. Comfrey root benefits were previously obtained by creating a paste with the root, similar to the methods of making creams and salves that are used today.³⁶

Comfrey plant has also demonstrated anti-fungal and antibacterial properties.³⁶

How Is Comfrey Salve Made and Used?

Contemporary literature and information strongly caution against internal use of Comfrey, but many people still include Comfrey ointment for external injury in their home remedies. Medicinal Comfrey salve can be made at home fairly easily.

(Image: Nancy Buron (nanseaj)⁵³)

Most recipes call for a small batch (one or two handfuls) of Comfrey leaves to be dried and then infused in oil. While olive oil and coconut oil are commonly used for infusion, individual preference can dictate the type of oil.

After infusion for about 6 weeks, the leaves can be strained out of the oil. Other ingredients are added to the oil, melted over simmering water, to thicken the mixture into a spreadable ointment or salve.

Ingredients commonly used include shea butter and beeswax. When all ingredients are combined, the concoction can be poured into a container and left to cool and set.³

Different oils and herbs can be added to achieve a desired aroma or therapeutic effect. The finished salve can be applied to the skin over minor cuts, bruises, swollen joints, contusions, and so forth.

Avoid using long-term as adverse health impacts are still under investigation.

Is Comfrey Root Safe?

The safety of Comfrey root and other Comfrey plant parts is still being evaluated, but there are a few things that are now certain. All parts of the Comfrey plant contain pyrrolizidine alkaloids which have been shown to cause liver toxicity, lung damage, genetic mutations, and cancers in animal test subjects.

Some individuals who have consumed Comfrey also experienced liver fibrosis and cirrhosis as well as hypertension and occlusions in the veins in and around the liver.³⁶

For these reasons, Comfrey plant is no longer recommended for oral consumption. In fact, the Food and Drug Administration (FDA) advised against the sale of dietary supplements containing Comfrey in 2001,³⁸ cautioning manufacturers and consumers against it.

Comfrey products were further regulated by the Federal Trade Commission (FTC) which brought legal proceedings against various companies promoting Comfrey products without full disclosure of potential risks. Comfrey products should be clearly labeled as only for external use.^{9, 11, 39}

The FTC and FDA also advise against applying Comfrey products to open wounds, as alkaloids are more easily absorbed through broken skin. Research and development efforts may give rise to more products containing alkaloid-free Comfrey if the potential benefits signify the costs of R&D.

As of now, Comfrey products should only be used externally, on unbroken skin, for short periods of time. Use with caution!

How To Grow Comfrey at Home

Learning how to grow Comfrey in a home garden is fairly simple, as Comfrey plants are tolerant, versatile, hardy, and fairly low maintenance. The most important trick to remember is that Comfrey spreads both by self-seeding and underground rhizomes, so it is a good idea to plan accordingly.

This may mean deadheading the flowers as they die out before seeds can develop or even growing Comfrey in a container so that root shoots are controlled. Otherwise, a gardener may spend more time than desired digging out unwanted Comfrey plants and all their plant parts as small root pieces left underground can develop into new plants.

Planting Tips for Comfrey Plants

Although Comfrey is relatively easy to grow, there are a few planting tips for Comfrey plant to consider. For example, knowing when to plant Comfrey for the best yield can increase the success of first-year crops.

New plants can usually be started in the ground in either fall or spring in areas where winters are not too harsh. To give the plants a leg up, some gardeners elect to start the seeds indoors in the fall so they will be ready to transplant outdoors in spring.

(Image: Nancy Buron (nanseaj)⁵¹)

Once established and new leaves are visible, the Comfrey plant grows very quickly.⁵

Always consider how far apart to plant Comfrey before putting the plants in the ground. Most sources recommend allowing about two feet between Comfrey plantings to permit them adequate air circulation and room to grow.^1,28

Growing a Comfrey Plant From a Seed, Cutting, or Seedling

Growing a Comfrey plant from a seed, cutting, or seedling in a backyard garden is among the easiest ventures for a gardener trying out new plants. When growing by seed, seed can be started outdoors in the fall or early spring or began indoors in a growing stratum and transplanted as seedlings in mid-spring.

When growing from cuttings, gardeners need to use the roots. During the spring, cut about 3 inches of the root right below the soil and plant the root division into its new home.⁵

Crown divisions can also be used by dividing mature plants into segments and replanting them.¹

Although Comfrey plants are pretty self-sufficient most of the time and can even tolerate dry spells, they do not thrive in periods of extended heat and drought. During these times, extra efforts should be made to meet the watering needs for Comfrey plants, particularly juveniles.

Thorough soaking of the roots or base of the plants weekly or twice weekly should do the trick.¹

Best Growing Conditions for Comfrey Plants

The best growing conditions for Comfrey plants depend upon what the gardener is hoping to achieve. An individual seeking to grow an isolated plant for appearances or for herbal use may want to grow their Comfrey in a container to prevent rhizomatous spread.

(Image: Hans⁵⁰)

In contrast, a person wanting to grow Comfrey as ground cover would want to plant in an open area with room to spread. Given its nutrient fixing properties, some people elect to plant Comfrey near plants and trees that can use those nutrients.

Comfrey plants prefer moist, well-draining soil rich in organic matter. It thrives in full sun to part shade.²⁸

Comfrey Plant Growing Zones

The common Comfrey plant grows best in temperate climates, and the Comfrey plant growing zone reflects that preference.

The best growing zones for Comfrey plant (where to grow Comfrey plant), are zones 4a through 8b (see USDA Plant Hardiness Zone Map to find your zone).^28,40

Companion Plants for Growing Comfrey

Given its significant phosphorus, nitrogen, and potassium content, Comfrey makes a great companion plant for hungry food plants, like tomatoes, potatoes, eggplants, and other members of the nightshade family. Many heirloom plants grow well in close proximity to Comfrey.

Other companion plants for growing Comfrey that should be considered in foodscaping or landscape gardening are fruit trees, as Comfrey grows well in their shade and helps to suppress weeds.⁶

How To Stop Comfrey Plant Disease

There is not a lot of available information on how to stop Comfrey plant disease as Comfrey is fairly disease resistant. It is known to be affected by a fungal disease called Comfrey rust (Melampsorella symphyti), which will overwinter in the roots of the plant.

A rust diagnosis usually means the plant will need to be removed and destroyed, making Comfrey plant disease prevention very important. This is best achieved by growing disease resistant cultivars such as ‘Bocking 14.’¹⁰

Additionally, there are not many pest problems with Comfrey, and Comfrey is actually considered a pest deterrent by many people as it attracts predator insects. The most common pests of the Comfrey plant are snails or slugs which may eat holes in the foliage.³⁷

Many gardeners have found that the best natural pest control for Comfrey plants is to put piles of cut Comfrey around the perimeter of the garden to divert slugs and snails as they creep toward the plants.²

How To Identify Comfrey Plant

Knowing how to identify Comfrey plants is useful for a whole host of reasons. A gardener may be interested in growing Comfrey plants strategically to fix nitrogen for surrounding plants, to use Comfrey plant parts to make plant fertilizer, to attract bees and beneficial insects, and to repel unwanted pests.

Conversely, the ability to recognize Comfrey plants is also very useful for individuals who want to control or eliminate Comfrey plants that may become invasive or because they are concerned about toxicity for household pets, children, and so on.

Finally, there is another subset of individuals who want to grow Comfrey in their herb garden to make their own topical ointments. All of these individuals need to know how to recognize this plant.

Most common Comfrey plants grow to about 3 feet in height, though some specimens may reach 5 feet. They spread via rhizomes, forming dense, leafy clumps.

The plants, in general, are hairy, even bristly along their winged stems. The plant is lightly fragrant.

Identifying Comfrey Flowers

The common Comfrey plant can be recognized by its creamy white to yellow flowers, which resemble those of bluebells, but some Comfrey plants may have pink or even purple flowers. Comfrey flowers are tubular, bell-shaped flowers which droop in clusters.

The individual flowers are small, less than one inch in length, but the clusters can be quite showy. Comfrey typically blooms in May and June.²⁸

Identifying Comfrey Leaves

Comfrey leaves, along with the flowers, are among their most defining aboveground features. The fragrant leaves are simple and arranged in a rosulate form around the stem.

Each leaf is lance-shaped, growing to 6 inches or more in length with a width of 3 inches or more at the base.

The leaves have margins which are entire (not toothed or lobed), and they are coarsely textured with rough hairs. The leaves grow upward on long petioles before fanning out.^1,28

Identifying Comfrey Seeds

As the flowers die back, they are replaced by Comfrey seeds, a cluster of four small nutlets which are shiny brown-black at maturity. The shape of the individual seeds resembles a small kernel of popcorn or a tiny egg.²⁷

Common Comfrey Plant (Symphytum officinale) Facts

The number of recognized species in the genus, Symphytum, ranges from 27, according to the Royal Botanical Gardens at Kew, to nearly 60 according to other sources.^17,31

A 2019 publication on the genus, available through the National Library of Medicine, places the number of species at approximately 35.³⁶

Members of Symphytum, commonly known as Comfrey, are flowering plants in the Boraginaceae family which originate primarily in Europe and Western Asia but have been introduced to many parts of the world, including North America.³¹

The type species Comfrey plant is the common Comfrey, or Symphytum officinale, the primary focus of this plant guide. Symphytum officinale is a temperate Eurasian native flowering herbaceous plant which grows up to 3 feet in height.

It has a clump-forming, spreading habit and can become weedy. The common Comfrey plant is well established in North America and across the United States.²⁸

(Image: Couleur⁵²)

The common Comfrey (and its relatives) plant’s long-term use in herbal medicine has contributed to the lore surrounding this genus and species and ample Comfrey plant symbolism. Its common names of “Boneset,” “Bruise Wort,” and “Knitbone” illustrate the widespread belief that the plant promoted the healing of wounds, and for thousands of years, it was used as such.³⁶

However, contemporary research has demonstrated that belief does not equate to fact.

Peruse the Comfrey plant facts below for more.²⁷

1. The common Comfrey plant was introduced to the United States during the 17th century. It was cultivated for use as a medicinal Comfrey plant and as a food crop.⁷
2. The roots of the Comfrey plant were often brewed as a tea or used in ale to relieve aches and pains. Poultices were also made from the plant for external use.²⁷
3. The pyrrolizidine alkaloids contained within the Comfrey plant have been found to cause lung damage, cancer, and serious liver toxicity when ingested.^7,28
4. Topical applications of the plant, particularly to open wounds, is no longer recommended as these alkaloids may be absorbed through the skin.
5. In the United States, the sale of products made from Comfrey plants intended for internal use or use on open wounds is banned.⁷
6. Comfrey plant extracts that are alkaloid free may be marketed for external use, but more research on safety and efficacy is needed.¹⁶

Other Types of Comfrey Plant

There are many other types of Comfrey in the genus, Symphytum, and this section highlights some of the most prominent species and their properties.^13,17

It boasts dainty, vivid blue flowers which hang from arching stems. It spreads rapidly via rhizomes.^22,23

It is perennial, sometimes biennial, and has pale yellow flowers.^12,14

5. Iberian Comfrey

(Symphytum ibericum)

Native to the country of Georgia in the Caucasus region, the Iberian Comfrey or dwarf Comfrey, this petite flower can make a nice addition to wildflower and wildlife gardens and can be grown as ground cover.

Like most of its relatives, it spreads via rhizomes and may spread vigorously when conditions are favorable. Flowers are creamy white to pale yellow.^8,26

It is often classed as a noxious weed in non-native territories such as the U.S. due to its vigorous spreading and difficulty of management.^{13, 15, 18}

Sometimes called the Quaker Comfrey, Symphytum x uplandicum is considered the most commercially significant Comfrey variety.

It grows up to 6 feet in height and displays small pink flowers.³³

Although the Comfrey plant is no longer considered safe for human or animal consumption, it still has some practical uses. Comfrey can be used as a pest deterrent, a fertilizer, or an ointment for short-term external use.

Given the serious health problems tied to its long-term use, Comfrey products should only be used with extreme caution and under a physician’s supervision.

However, there is still promise for the Comfrey plant as a medicinal resource if science can reliably isolate the beneficial compounds for use while eliminating harmful ones.