Comfrey: what you need to know about the plant that ‘looks like borage a few gins over a long weekend’


Mark Diacono on the beautiful and wild joy of comfrey.

Comfrey is an upright, clump-forming perennial that looks a bit like borage a few gins for a long weekend. Its pointed leaves – somewhat hairy and papery to the touch – are borne beneath drooping clusters of pinkish-purple and white flowers that appear from spring through summer. It’s quite beautiful in its untamed way.

It grows rapidly, reaching around 30 inches tall and wide within a few months. Meanwhile, its roots dig deep into the soil, drawing otherwise inaccessible minerals into the plant to accumulate above ground, making it a naturally rich source of the holy trinity of plant nutrients – nitrogen, phosphorus and potassium – which can bring such benefits to the rest. of the garden. Its richness in potassium is particularly valuable for fruit plants.

There are several ways to put these nutrients to good use. First, comfrey tea. I make it several times a year, starting in the spring. The easiest way is to fill a mesh bag (I use an old onion net) with torn comfrey leaves and hang it from a cane in your water catcher. For about a month, it will slowly leach its minerals into the water; you’ll know when it’s ready to use, because it smells like something with very poor power died a long time ago. It should be the color of a very weak tea. Dilute it if necessary, as anything stronger is a waste.

Alternatively, you can turn a large water bottle upside down (leave the cap off), cut off the bottom, and fill the bottle with comfrey leaves. Place a brick or similar on top. Over the next fortnight, the leaves decompose under the weight of the brick and release a dark liquid. To use, simply unscrew the lid, decant what you need and dilute it with about 15 parts water. Once established, you can take three or four cuttings of comfrey over the growing season, providing free nutrients and, in turn, more delicious produce.

Common comfrey (Symphytum officinale) in full bloom.

The potassium in comfrey tea is especially good for all fruiting plants; most of mine goes on eggplant, peppers, tomatoes, zucchini and beans. I give them a good watering fortnightly from flowering, which they repay later in the season with a bigger and healthier crop. If you have vines or stone fruits, you can use comfrey tea as a foliar feed, spraying it directly onto the leaves where it will be easily absorbed.

For plants that need nitrogen for green growth – peas, beans, cut and pieced leaves, etc. – you can follow exactly this method, but using nettles. Not that it smells any better.

If you have fruit trees, you could do worse than plant comfrey around the base of the tree, leaving about a foot of the trunk. It will mulch any grass that competes with the root zone of the tree, flowers bring pollinating and naturally predatory insects to pests and the simple act of mowing or pruning the leaves will act as a cut and return mulch that releases minerals and nutrients in the root zone of the tree as it degrades. If you are growing potatoes, lay an early cutting of the leaves under each seed potato; they will fertilize the developing crop as they decompose.

Comfrey also acts as a powerful compost accelerator. Even if you get the right mix of greens and browns, comfrey or nettles – in shredded leaf or liquid form – added to the pile will make everything move faster.

Generic comfrey might work well for you in an orchard situation or if you have some space to devote to it, but, for a little more control over its spread, look for Bocking 14 seedlings. These are self-sterile and do not therefore do not produce seeds, so they will not spread the patch as common comfrey can.

To start or extend a patch of comfrey, you can start with seeds or young plants. If you already have one, simply dig up a root in the winter, cut it into £1 slices and bury it an inch into a 3½ inch compost pot and let the roots grow, before the planting in late spring.

Comfrey can live 20 years or more, so choose a location carefully. avoid chalky soils and give it at least partial sun and it should thrive. Although it may be tempting to dig up some wild comfrey to start, it tends to be much less productive, less nutrient dense and less healthy than garden comfrey.

Mark Diacono grows edibles, both the usual and the unusual, at Otter Farm in Devon ( Son From Scratch: Ferment (Quadrille, £12.99) is out now

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