If you were to create a list of the most important plants for a healthy garden, innocuous-looking comfrey would be high on that list. It might look like a leafy giant that pops up everywhere, but comfrey is an important herb, both for your health and the health of your garden. The plant has long, deep-green leaves with bell-shaped white, blue, or purple-hued flowers on the top. Bees love it, particularly bumblebees, and it is a good way to attract these beneficial pollinators to your garden. For many years, its leaves have been a boon for gardeners, who use them as a natural fertilizer and mulch.
Comfrey is a useful fertilizer plant for your vegetable or herb garden. Photo: Smoobs / CC by 2.0
Starting and Growing Comfrey
Comfrey grows up from the roots every year, and it’s easiest to start by splitting a friend’s comfrey root into pieces. Since it spreads so easily from pieces of the root, be aware that when you split or move it you may end up with comfrey in other areas of your garden. Bury small sections of root at least 2 inches deep in the garden, in rich, damp soil. Comfrey grows very tall over the course of the spring and summer months, and it takes in large quantities of nitrogen from the garden. It loves soil that’s been amended with aged manure.
While comfrey will grow in many different environments, it prefers rich, slightly damp soil. In its first year, allow it to grow without harvesting it. This allows the plant to become strong, and you’ll get a good crop of leaves in the second year.
Harvesting Comfrey
Why would you harvest comfrey leaves? The plant is particularly talented at accumulating nutrients from the soil, and this means that the leaves make an amazing mulch for your garden. Add them as a side dressing on vegetable beds, creating your own natural, slow release fertilizer. You can also place a few leaves into your compost to enrich it and activate it.
Comfrey can also been used as a salve and a poultice to heal rashes and swelling. Take care, since some people are sensitive to the tiny hairs on the leaves. It should not be used on open wounds and should not be eaten.
Bumblebees love comfrey flowers. Photo: nickodoherty / CC by 2.0
Harvest your comfrey up to five times in the growing season. Its long green leaves grow quickly, and they’re ready to harvest when they are about two feet tall. Cut the plants right down to a few inches above the ground. Since plants put a lot of energy into reproduction, it’s best to harvest comfrey leaves before the plant flowers to get the most nutrient-rich leaves for the garden. Harvest the leaves until late summer, then allow the plant to remain unharvested for a while before the winter months.
Types of Comfrey
There are several types of comfrey, all in the Symphytum genus. Common Comfrey is called Symphytum officinale, and it has viable seeds. This makes it a little invasive in the garden. Rough Comfrey (Symphytum asperum) is a wild variety of the plant. It has blue flowers and spreads vigorously, making it a poor choice for a small, enclosed herb garden. Russian Comfrey (Symphytum x uplandicum) comes in different varieties. The Bocking #4 variety is particularly good as an animal feed, since it’s high in protein. It’s also drought tolerant. The Bocking #14 variety is an excellent mulch plant and is sometimes soaked in water to create compost tea, a liquid plant fertilizer. This type of comfrey doesn’t have viable seed so it won’t spread like Common Comfrey. It does spread well from pieces of its root. If you’re looking for comfrey that’s easy to reproduce but manageable in a small herb garden, look for a piece of Russian Comfrey.
Comfrey is an incredibly useful mulch and fertilizer that is packed with nutrients for your garden. While you could go out and buy commercial fertilizers, why not try growing some in your herb garden?
It should be noted that Comfrey can easily take over your garden if it’s not carefully controlled.
Also, Comfrey should be used sparingly, if at all, as new studies on the plant have shown it to have carcenogenic properties. It also contains a hepatotoxic, called pyrrolizidine alkaloid, which can be absorbed even through unbroken skin. Those with pre-existing liver damage or illnesses, or those who are taking medications which may damage the liver, are at the highest risk.
Sabrina – All of the studies I’ve read were in conjunction internal use which is why our author specifically recommended against eating it. I do agree that anyone with liver damage should avoid comfrey also.
Sabrina – yes, I would only use gentler herbs like plantain or yellow dock on wounds – comfrey is not for use in those situations. As I mentioned above, my experience with comfrey has been that the Russian type spreads through pieces of the root. If you’re digging a lot in the garden or harvesting and cut too low, there is potential for the comfrey to spread. Some find it a nuisance. Since I use it as a bee and mulch plant, I don’t mind if it pops up in new places, but I will transplant it if it’s in a place where it doesn’t really fit.