Okay, so the identity of this one is a bit of a trick question, as it is not edible. What is it? *, and what is its relation to food production?
This plant, located in several places around our garden, has a large central tap root and huge, lush leaves. It puts out these delightful flowers ranging from purple to white, yet the plant does not reproduce via the flowers, as it is sterile. (Whatever you do, though, do not cut the tap root, or the plant will pop up everywhere!)
It is highly advised not to eat the plant, as it can lead to liver failure with its hepatotoxic pyrrolizidine alkaloids. However, with a country name of “knitbone”, topical application can encourage cell division leading to faster healing.
Why did we plant about ten of these big boys? Because the leaves make excellent, nitrogen-rich compost and fertilizer! The large tap root, which can extend dozens of feet into the soil, pulls nutrients from well below the surface, concentrating all the mineral goodness into their leaves and stems. Whether we add the leaves to the compost pile, drop them where they are, or make a “tea” from the leaves, this is one of the best forms of ‘free fertilizer’ for the other, edible plants.
* Russian Comfrey (Symphytum × uplandicum)
This image is created from a focus-stack of eight images, with a Nikkor 105mm macro lens.