A weed is but an unloved flower.
~Ella Wheeler Wilcox
Comfrey: invasive perennial or super-garden plant? Maybe a bit of both… though I definitely lean towards the latter. Comfrey is a perennial herb (or to some a “useful weed”) and a member of the borage family. The thick roots tap deeply into the layers of soil mining the nutrients and storing them in the green tongue-shaped leaves. Comfrey leaves contain more nitrogen, phosphorous and potassium (N-P-K) than farm animal manures and more nitrogen and potassium than garden compost. Comfrey leaves also contain calcium and iron. The leaves are excellent for composting and when used as a mulch, break down readily without robbing the soil of precious nitrogen. Pretty super, right?!
Comfrey is quick-growing and forms a spreading clump in sun or shade. Depending on the variety, it can range from ten inches to three feet tall. All varieties die back to the ground in winter. The whisker-leaved plants produce nodding bell-shaped flowers that are a magnet for bees and other pollinators. Once established it takes a lot of digging to remove comfrey roots from the soil (trust me, leave even a tiny piece and the plant will return) so take care in selecting a spot for it to thrive. That said, I simply pull up clumps of the plant and toss them into the compost pile as the season goes on. Common comfrey (Symphytum officinale) also reseeds heavily, hence the “invasive” and “weedy” labels. If you don’t want a yard full of comfrey (or you aren’t a fan of dead-heading) Russian comfrey (Symphytum x uplandicum) produces very little viable seed and will remain for years where you plant it. Russian comfrey is also said to yield the greatest benefits in the garden as a fertilizer. (Check back Monday for more on comfrey’s uses in the garden.)
The easiest way to grow any comfrey is from root cuttings. Lift a clump and cut the black rootstock into two-inch pieces. Plant the cuttings just under the soil’s surface, water well and in about a week new plants will emerge. (Young foliage is susceptible to attack from hungry slugs so take precautions!) Once growing, a monthly feeding of liquid kelp is plenty to satisfy comfrey’s green need for nitrogen, though I confess I’ve never fertilized my comfrey and it still grows like crazy! New comfrey plantings should be allowed to become established for one year before harvesting the leaves for use.Once well-established, the plant can be cut back to 2″ above the soil throughout the season and the leaves used in compost or to make comfrey garden tea.
Near the end of the season, around the middle of August, leave the plants to grow and flower without further cutting so they’ll remain vigorous and healthy the following year. After three years the plants can be dug up and divided regularly. To divide ours, I simply plunge the spade into the plant in early spring when the leaves emerge and lift a chunk to move. The divisions die back when planted, give them a week and they’ll recover and start growing all over again.
I’m experimenting with several different methods for using comfrey in the garden this year. If you’d like to know more about what I’m trying please check back for my next post on Monday. Happy gardening!