Share This Page

garden q&a: comfrey more bad than good

| Saturday, Oct. 27, 2012, 8:54 p.m.
Comfrey (Symphytum) Credit: Jessica Walliser

Q. I have attached two pictures of a plant that the old owners of our house had planted. There are hundreds of them. My neighbor has told me that he was told by the old owners that they were for “medicinal” purposes. We have been looking online to identify them, but have came up with nothing. We just cannot figure out what they are or what they are used for. Of course, the old owners are no longer living to ask. Can you help?

A. The plant you inherited is comfrey (Symphytum), though I can't tell from the pictures the exact species you have. Regardless, this plant bears small bell-shaped flowers in cream, purple or pale pink. The leaves and stems are covered in tiny hairs that can be quite irritating to the skin, so be sure to wear gloves and a long-sleeved shirt when working with it. It is a fast-growing plant that is generally trouble free in regard to pests and diseases.

However, as you have discovered, it also can be aggressive, spreading via its root system as well as by seed. If you want to get rid of the plant, you'll have to dig it up carefully and remove as many of the roots as possible as each root piece you leave behind readily sprouts into a new plant.

The roots of comfrey are nutrient-grabbing thugs, making them a poor neighbor to other plants. However, the nutrients they pull from the soil readily travel to the leaves where they accumulate, making the freshly cut leaves an interesting source of nutrients to other plants. People use moderate amounts of newly harvested comfrey leaves as a compost activator, to enhance the rate of decomposition through the rapid addition of nitrogen they provide. The foliage also is used to make a liquid fertilizer by steeping it in water for a few days and watering with the resulting liquid.

I've also read about gardeners who use the freshly harvested leaves as mulch, layering them around plants in the vegetable garden.

As far as the medicinal purposes your neighbor told you about, the only way comfrey can be used is as a topical skin treatment and, even in this form, its use should be very limited. Comfrey should never be ingested in any form as it contains compounds that can lead to liver failure. The USDA has banned the use of comfrey in any digestible products or supplements.

Horticulturist Jessica Walliser co-hosts “The Organic Gardeners” at 7 a.m. Sundays on KDKA Radio. She is the author of several gardening books, including “Grow Organic” and “Good Bug, Bad Bug.” Her website is www.jessicawalliser.com.

Send your gardening or landscaping questions to tribliving@tribweb.com or The Good Earth, 503 Martindale St., 3rd Floor, D.L. Clark Building, Pittsburgh, PA 15212.

TribLIVE commenting policy

You are solely responsible for your comments and by using TribLive.com you agree to our Terms of Service.

We moderate comments. Our goal is to provide substantive commentary for a general readership. By screening submissions, we provide a space where readers can share intelligent and informed commentary that enhances the quality of our news and information.

While most comments will be posted if they are on-topic and not abusive, moderating decisions are subjective. We will make them as carefully and consistently as we can. Because of the volume of reader comments, we cannot review individual moderation decisions with readers.

We value thoughtful comments representing a range of views that make their point quickly and politely. We make an effort to protect discussions from repeated comments either by the same reader or different readers

We follow the same standards for taste as the daily newspaper. A few things we won't tolerate: personal attacks, obscenity, vulgarity, profanity (including expletives and letters followed by dashes), commercial promotion, impersonations, incoherence, proselytizing and SHOUTING. Don't include URLs to Web sites.

We do not edit comments. They are either approved or deleted. We reserve the right to edit a comment that is quoted or excerpted in an article. In this case, we may fix spelling and punctuation.

We welcome strong opinions and criticism of our work, but we don't want comments to become bogged down with discussions of our policies and we will moderate accordingly.

We appreciate it when readers and people quoted in articles or blog posts point out errors of fact or emphasis and will investigate all assertions. But these suggestions should be sent via e-mail. To avoid distracting other readers, we won't publish comments that suggest a correction. Instead, corrections will be made in a blog post or in an article.