Location of Comfrey
Comfrey is a member of the Boraginaceae family whose major noticeable characteristics include bluish flowers and bristly hairs and is of the genus Symphytum. There are three plant species in the genus Symphytum that are relevant to the crop known as Comfrey. Wild, or common Comfrey (Symphytum officinale) is native to England and extends throughout most of Europe into Central Asia and Western Siberia. Prickly or rough Comfrey (Symphytum asperrimum), named for its bristly leaves, was brought to England from Russia around 1800. Quaker, Russian, or blue Comfrey originated as a natural hybrid of S. officinale and S. asperrimum. This hybrid was called Caucasian or Russian comfrey in reference to its country of origin. Cuttings of this hybrid were shipped to Canada in 1954 and it was named Quaker Comfrey after the religion of Henry Doubleday, the British researcher responsible for promoting Comfrey as a food and forage plant. The majority of Comfrey grown commercially in the United States appears to come from these same plants shipped to Canada and derived from the British Bocking Mixture (the place where they were grown is Bocking, England), which is a mix of several clones that differ slightly in plant vigor and general organic structure.
The Comfrey plant is a low, dense shrub whose stems can reach three to five feet in height. Being a perennial herb, it dies back in the winter. The leaves are coarse and hairy; clasping and alternate (without stipules) on the stem and their margin is entire. The size of the leaves ranges from five to twelve inches becoming progressively smaller toward the top of the plant. The flowers are purplish, white or pale yellow and each single one is tubular shaped and about a half inch in length. They come in a cyme (cluster of 15-20 flowers per peduncle) and are scorpioid in their growth pattern. The calyx consists of five sepals, the corolla is five lobed and the flower has five anthers. The nutlet is deeply embedded in the calyx of each flower. The roots are short, thick and tuberous and the entire root system is expansive and grows as deep as eight feet into the ground.
The plant requires deep, though not necessarily good, soil for cultivation. Productivity is not very sensitive to soil pH, but highest yields occur on soils with a pH of 6.0 to 7.0. The ideal planting times are in the spring and Comfrey is best propagated by division, not seed. It produces its highest yields in full sunlight and under cooler conditions, though, it is drought resistant due to its extensive root system. It prefers moist, fertile soil, but is adaptable to many kinds of soil. Comfrey plantings are known to last indefinitely (more than twenty years) if soil fertility and proper weed control are maintained and are best planted three to four feet apart from one another. Comfrey is a high-protein forage that obtains all of its nitrogen from the soil; therefore, this nutrient must be added to the soil through composting and fertilization. It drives its roots deep into the soil, bringing up calcium, phosphorus and potash, as well as many trace elements.
Diseases are not a serious problem here in the United States. In England, Comfrey rust fungus (Melampsorella symphyti) overwinters in the roots and reduces the amount of old plantings harvested, but this disease has not spread to the U.S. due to plant quarantine regulations on the importation of plants or roots. There haven't been any insect problems reported in the U.S. related to Comfrey.
Comfrey is also recommended as a fertilizer in the garden because its carbon to nitrogen ratio is about 14 to 1. When compost is made we are using bacteria to lower the proportion of carbon to nitrogen compounds in order to produce heat. It is compost which makes a garden into a thriving place, too, because it makes the minerals and nutrients that plants need readily available to them. The average ratio of carbon to nitrogen is 10 to 1. Therefore, Comfrey is nearly compost before it goes on the heap! The following is a recipe for Comfrey fertilizer:
“Pick a good sized handful of leaves. Place them in a container with enough water to cover the leaves. Cover and let this cook for 4 weeks in cool weather or 2 weeks in hot weather. Then squeeze the leaves to extract as much juice as possible. Strain and use at a rate of 1/3 cup of comfrey juice to one gallon of water. Use as a foliar feed and soil drench around the plants....the smell while it is cooking is strong!”
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