Comfrey (Symphytum officinale) is a historical, perennial herb recognized for its rapid growth and deep root system. This allows it to function as a green manure or a valuable ingredient in topical remedies. Its ability to accumulate nutrients makes it popular in sustainable gardens. When searching for planting material, buyers must choose between seeds and vegetative cuttings, which reflects a significant difference in how the plant is propagated.
Why Comfrey Seeds Are Rarely Used for Propagation
Many people search for comfrey seeds, but this is unreliable for establishing the most desired varieties. The preferred type, Russian comfrey ‘Bocking 14’ (Symphytum x uplandicum), is a sterile hybrid. This sterility prevents the plant from producing viable seeds, which stops aggressive spread in the garden.
True comfrey (Symphytum officinale) does produce seeds, but they have low viability and unpredictable germination rates, often requiring cold stratification. Even if seeds germinate, the resulting plants show genetic variation and may not possess the desirable characteristics of ‘Bocking 14’. Vegetative propagation, using root or crown pieces, bypasses these issues and offers a faster, more reliable way to produce a clone.
Recommended Sources for Comfrey Root Cuttings and Crowns
Since seeds are impractical, focus on purchasing root material, the established method for propagating the best varieties. Look for “root cuttings,” “crowns,” or “bare-root plants.” Crown cuttings establish more quickly and reliably than root cuttings, which are sections of the taproot.
Reliable sources include specialized online herb nurseries and organic suppliers catering to permaculture or medicinal herb growers. These vendors typically stock specific cultivars like ‘Bocking 14’ and provide planting instructions.
Local horticultural societies or garden swaps are also excellent places to find comfrey, as established plants can be easily divided and shared. Verify the supplier’s reputation to ensure you receive the correct variety, especially ‘Bocking 14’, as misidentification can lead to unwanted spread.
When ordering, you receive a chunk of the crown or a small root section that will quickly sprout. This material is often shipped year-round, but spring and fall are the best times for planting.
Essential Safety and Sourcing Guidelines
When sourcing comfrey, seek out the sterile ‘Bocking 14’ cultivar (Symphytum x uplandicum). This hybrid is non-invasive because it cannot spread via seed, making it easier to manage than wild varieties. Although ‘Bocking 14’ is sterile, the plant will spread if its deep roots are disturbed, so the planting location should be considered permanent.
Comfrey contains pyrrolizidine alkaloids (PAs), compounds known to be hepatotoxic if ingested. Therefore, the consensus among experts is to restrict comfrey use to external applications only, such as salves or compresses. The roots and young leaves contain the highest concentration of these alkaloids.
To ensure safe handling, wear gloves when harvesting the leaves, as the coarse, hairy foliage can cause skin irritation. Plant comfrey in a dedicated area where the soil will not be tilled or dug up. Any broken piece of root can regenerate into a new plant, so permanent placement prevents accidental spread and reduces the risk of root fragments moving to other parts of the garden.