Sturdy comfrey thrives anywhere — and feeds everything in your garden

FALL IS ALWAYS a good time to assess the recent growing season and make notes to your future self about garden gains, losses and the occasional horticultural mishap.

For instance, do not plant comfrey. You will never get rid of it. I avoid toxins of all sorts in the garden, but I am merciless with a trowel, a shovel or a mattock when it comes to plant removal. After more than 15 years (and an excavator!), I give up. The comfrey is here to stay.

A couple of large clumps of comfrey at the margins of our property are the result of haplessly tossing a dug-up plant onto the weedy verge of the gravel driveway to wither and die in the afternoon sun so I could dispose of the remains in the clean green cart — I wasn’t about to risk my personal compost bin. Apparently, as often happens, I got distracted. Today those clumps are thriving, right where they landed.

Comfrey (Symphytum officinale) is a free-flowering perennial with lush broad-leaved foliage that almost looks tropical — picture a bristly hosta. All summer long, the plant produces numerous arching wands of nectar-rich purple blooms that pollinators love.

In the lexicon of permaculture, comfrey is known as a dynamic accumulator. The resilient taproot that makes it so (very) enduring delves deep, mining the subsoil for micronutrients and minerals such as potassium, phosphorus, calcium, iron and magnesium, which are then stored in the plant’s “biomass.” Turns out, comfrey is a viable source of homegrown fertilizer.

I’ve adapted to the comfrey’s immutable location and now manage it as part of my regular garden tasks. Three to five times a year, about once a month throughout spring and summer, I harvest the comfrey, cutting it down to about 3 inches.

It goes without saying that such harsh treatment doesn’t even faze this hardy herb that requires no supplemental water and is absolutely pest-free. Summer-worn foliage might develop a touch of powdery mildew, but just keep up with your cutting regime, and fresh foliage will rebound with alarming alacrity.

Comfrey is rich in potassium — I’ve read where its NPK ratio (nitrogen, phosphorus, potassium) approaches that of a farmyard manure. So these days, I exploit comfrey’s hearty constitution and nutrient-rich leaves to feed flowers and fruits in my garden — for free!

Fresh comfrey leaves are high in nitrogen and break down very quickly. Added directly to the compost bin, comfrey activates microbes and fires up decomposition. Pro tip: Allow leaves and stems to wilt in the sun on a tarp or solid surface to prevent accidentally contaminating the pile, or inadvertently planting comfrey where you don’t want it. A feeding mulch of fresh or dried comfrey leaves layered directly on the soil around tomatoes, peppers and other fruiting plants boosts flowers and fruiting.

Or brew a bucket of comfrey tea — a malodorous herbal stew and a potent liquid feed — by steeping comfrey leaves in a bucket of water left in the sun for a couple of weeks. You’ll want a lid on the bucket to contain the stench. Strain the resulting concentrated tea, and dilute the mixture 1:3 with water. Apply the resulting tonic to roots as a soil drench, or for over plants as a foliar feed.

I might never get rid of the comfrey, but the stems on my sweet peas have never been longer.

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