Russian Comfrey is a great plant in the garden, when planted in the right place (they can be hard to get rid of, so give it some thought before planting one). Russian Comfrey is a great plant to grow for making fertilizer, activating compost piles or to help supplement animal feed. You can chop off the greens and mulch your tree collard plants with them, or make a fertilizer tea by filling a bucket with the leaves and covering them in water then letting it ‘brew’ for a few weeks. The plants can grow to about 3′ wide and 3′ tall.
Russian comfrey is unfortunately not edible for humans but it is an important part of a small homestead to help with fertility cycles. The plants deep, vigorous root system can help it accumulate a number of important minerals that are then stored in its leaves and can become available to other plants when used as a mulch. We know one organic farmer who has maintained the fertility of one of his fields from a large comfrey patch growing nearby (about 1/2 the size of the vegetable bed). Three times a year he cuts the tops off the comfrey (he uses a scythe because it’s a large patch) and mulches the vegetable fields with the comfrey leaves. This could be done on a small scale in a home garden with just a few comfrey plants planted under a fruit tree or in a back corner to help build the soil.
Russian comfrey will not spread by seed (the seed of this variety is sterile) or the leaves, but they do tend to spread easily if you dig up the roots. Also, if you want to remove a plant they will readily regrow from any leftover roots, so it can be hard to get out that way. If they are too heavily shaded out they will eventually tend to die back. We like to plant them under fruit trees such as Persimmon, Plums and Mulberry.