Buy Symphytum uplandicum 'Bocking 14'

Bocking 14 is a sterile hybrid Comfrey which has the benefit of its robust growth and long-season flowers, but without any viable seed production. The plants spread slowly by the roots to form clumps of deep green foliage with dark purple flowers that start in mid-spring. It is an absolute favorite with many of our native bumble bees and seems to be the most attractive flower for them of anything else we grow. Comfrey works well as a low-maintenance border plant where it is quite competitive with weeds, its fast growth and broad leaves smother the cool season weeds that sprout in the beds over the winter and Comfrey even seems to be competitive with tall, invasive grasses once it gets established. The roots are tolerant of a wide variety of soils and can handle sites that frequently switch between dry and wet, with plants going summer dormant in extreme drought and resprouting again from the roots after rain. The leaves are frequently harvested as a green manure due to their high nutrient content and the plant's ability to push new growth quickly even after multiple cuttings. Root sections will sprout new tops when planted about two to four inches deep, this makes propagation by division easy as you don't need to have both roots and parts of the crown for each division like many perennials. However, this also makes the plant difficult to remove by tillage as the severed root pieces will continue to sprout so in general it is recommended to plant comfrey in locations where you want it to remain for years. It can be killed easily by tarping over the plant for one season to prevent any leaves from reaching the sun, starving the roots. This is effective because it doesn't set seed that can resprout in the soil years later like with some other plants.