I have comfrey growing in my herb bed, but up until this year I have not used comfrey much in my vegetable garden. Occasionally when I chop the leaves back, I will lay them down on the vegetable beds, but that was the extent of my comfrey use.
Apparently this plant is a wonderful source of nitrogen and potassium for the organic gardener. Because its roots go deeply into the soil, comfrey is able to collect many of the nutrients in the soil into its leaves. This year I’m going to experiment with laying comfrey leaves on my potato beds and around my fruiting plants. The nitrogen is good for the potatoes and the potassium is good for the fruiting plants.
In my experience, comfrey roots easily, but it’s not quite as invasive as mint. It would be good as a background plant, but not as a focal point.