The flowers of True Comfrey (Symphytum officinale) are generally very richly arrayed and colored dark purple. The leaves are lance-shaped and not so broad as those of Russian Comfrey.
True Comfrey is really the nicest of the Comfrey clan in my opinion. From the luscious leaves to the thick, mucilage-laden roots I find nothing to compare. For years I thought Comfrey did not make seed, because I was not aware of the true plant, which is seed-productive, although the seeds are not so easy to collect. The seeds ripen and drop on an ongoing basis. They are large, shiny and black, wedge-shaped yet rounded, smooth and sensual to the touch.
They are best planted in very early spring in outdoor conditions, or given a good 30 days moist refrigeration before planting in the greenhouse or receptive garden bed. Seedlings grow fast and in time send down a good taproot. You really have to grow them for 2 years before adequate root yield can be obtained. In the mean time, the leaves can be harvested, preferably just prior to flowering. In Zones 4 to 8, it would seem reasonable to expect a summer harvest of leaf in the first year, and at least 2 harvests of aerial parts per summer in successive years.
I use fresh comfrey leaf for feed, veterinary, and compost purposes; dried comfrey leaf in salve; the fresh root as a poultice. I could not long live without Comfrey.