Have you ever read about a plant and thought “I just have to find some?” Well, that’s how I felt when I started researching growing comfrey. It’s like the all purpose herb. You can use it to fertilize your garden, trees and yard, treat wounds and even feed to livestock (in small quantities). It’s truly an all purpose home and garden herb.
There are several varieties of comfrey, the most common being True Comfrey and Russian Comfrey. Both are grown and used in the same ways but there are a few differences.
True comfrey is the “original” comfrey and is what has been grown for medicinal purposes since ancient times. It’s also known as “knitbone” because of it’s ability to help heal bone and skin injuries.
True comfrey is super prolific and can be harvested several times during it’s growing season. Since it readily self seeds, it’s important to harvest true comfrey before it sets seeds. If you harvest after it flowers, be sure to remove the flowers before using the comfrey leaves around the garden. If you don’t want a lot of volunteers in your garden, you’ll need to be diligent about this.
Russian comfrey (Bocking 14) is actually a hybrid between true comfrey and prickly comfrey, both of which, are pretty invasive by self seeding. However, Russian comfrey has sterile seeds so you don’t have to worry about it spreading by seed.
Russian comfrey is also super prolific and can be harvested several times during the season. It’s propagated from the roots so there’s no concern about using the flowers in the garden.
As the comfrey grows, the root system will expand and will eventually need to be divided.
I prefer to grow Russian comfrey since I don’t think I’m diligent enough to keep true comfrey from taking over my property. I get my rootstock from Buy Comfrey. They have great prices and great service.
How to Grow Comfrey
To start growing comfrey you need to get seeds (for True comfrey) or rootstock (for Russian comfrey), other than how they’re started, both varieties are grown the same.
Comfrey likes full sun and fertile soil, but will tolerate some shade and a variety of soils. I think it’s easiest to start comfrey in pots since the soil needs to stay moist until it spouts. But it can be started directly in the garden, too. Once they get their second set of leaves, I move plant them where I want them.
When planting comfrey, you can dig a hole about 10″ across and 1-3 feet deep and add lots of compost to it. Then plant the comfrey in it and water well.
You can grow comfrey in pots but since they have such a long taproot you want to use a pot that it’s deep (like a 5 gallon bucket).
Comfrey is cold and heat hardy and can survive temperatures from -40°F degrees to 120°F. It grows well in zones 3-9.
The taproot can grow 8-10′ long, so comfrey is often used to break up clay soil. Mature comfrey is drought tolerant and will mine the nutrients from deep in the soil. The nutrients are stored in the leaves which is why they are so great for mulching.
At maturity, comfrey is about 2 feet tall and about 3 feet in diameter.
It’s recommended that you don’t harvest comfrey right away. It’s best to let it get established, so wait at least three months before harvesting. Longer if you planted seeds.
After the comfrey is established you can harvest the leaves a few at a time. When the plants reach about 18″ you can do a big harvest and cut them back to about 2″.
Comfrey has the most nutrients just before it flowers. If you can, try to time your harvest so that you harvest before it flowers.
There are a lot of uses for comfrey in the garden, with livestock, and in the apothecary. I do want to mention that it’s not advised to use comfrey internally.
edited to add: I realize that there is some controversy surrounding the studies that caused this warning to be issued, however, I prefer to err on the side safety so I do not recommend that comfrey be used internally or on broken skin. There are safer herbs that can be used for any issue you would use comfrey internally for. Of course, you will need to make your own informed decisions for your family.
In the garden, you can use the chop and drop method and use the leaves to mulch the garden and orchard. As the leaves decompose they’ll fertilize the soil.
You can also plant comfrey in tree guilds, here’s a great guide from Tenth Acre Farm.
Comfrey can be used in fodder for livestock – not in large amounts but as part of a varied diet. Some people suggest letting the leaves wilt for a couple of days before offering it to the livestock, if they refuse it fresh.
I also use comfrey in some of our salves and make comfrey poultices with it.
Have you ever grown comfrey? Any pointers?