Editing Symphytum (section)

===Propagation===
{{more citations needed|section|date=May 2018}}

Bocking 14 is sterile, and therefore will not set seed (one of its advantages over other cultivars as it will not spread out of control); thus, it is propagated from [[root cutting]]s. The gardener can produce "offsets" from mature, strongly growing plants by driving a spade horizontally through the leaf clumps about {{cvt|7|cm}} below the soil surface. This removes the crown, which can then be split into pieces. The original plant will quickly recover, and each piece can be replanted with the growing points just below the soil surface, and will quickly grow into new plants. Offsets can also be purchased by mail order from specialist nurseries in order to initially build up a stock of plants.<ref name="teynor">{{cite web |vauthors=Teynor TM, Putnam DH, Doll JD, Kelling KA, Oelke EA, Undersander DJ, Oplinger ES|title=Comfrey |url=https://www.hort.purdue.edu/newcrop/afcm/comfrey.html |work=Alternative Field Crops Manual |publisher=University of Wisconsin, Extension, Cooperative-Extension|date=February 1992 |access-date=25 March 2014}}</ref>