How to grow Comfrey
Updated October 2026
Comfrey is a vigorous, deep rooted perennial with large, hairy leaves and drooping clusters of purple, pink or white bell flowers that bees love. Gardeners grow it to cut several times a year for mulch, compost and a potassium rich liquid fertilizer. It spreads readily and regrows from any piece of root, so choose its spot carefully, and do not eat it: comfrey contains liver damaging alkaloids.
📖 Our full guide: How to Grow Comfrey
Where to plant
Comfrey grows best in full sun to part shade in moist, rich, well drained soil, and it tolerates clay and drought once established. In hot summers, NC State notes it appreciates some afternoon shade. Plant it where it can stay for good, such as the end of a bed, beside a compost area or under fruit trees, because it sprouts again from any root left behind.
Plant in late winter in Florida, the Gulf South, Texas and the desert, in spring in California, the Mid-South, the Mid-Atlantic and the Pacific Northwest, and in May across the North. It is hardy to about zone 4.
Choosing a variety
Common comfrey (Symphytum officinale) sets seed and can spread around the garden. Russian comfrey Bocking 14, a sterile selection, does not set viable seed, so it spreads only where you plant it. It is grown from root cuttings and is the usual choice for a fertilizer patch.
How to plant
- Plant root cuttings or small crowns a couple of inches (5 cm) deep, about 2 feet (60 cm) apart.
- Water well until new leaves appear and the plants establish.
- Where you want to keep it contained, grow it in a large container or a bed edged with a barrier.
- Leave plants to establish before cutting heavily in the first season.
Watering and feeding
Water young plants regularly. Established comfrey has deep roots and tolerates dry spells, though it grows more lushly with steady moisture.
Comfrey needs little feeding. A top dressing of compost or manure in spring keeps it producing heavily if you cut it often.
Pruning and care through the year
- Cut the leaves several times a year, a few inches above the ground, and let the plant regrow.
- Cut flowering stems before seed forms on common comfrey to limit self seeding.
- To remove comfrey, dig out every piece of root, as any fragment left behind will resprout.
Cutting comfrey for the garden
Cut leaves for chop and drop mulch around fruit trees and vegetables, or add them to the compost pile. NC State notes the leaves are rich in potassium, which suits tomatoes.
For a liquid fertilizer, pack cut leaves into a bucket, cover with water and leave for at least a week, then dilute the dark, smelly liquid before using it around plants.
Growing in pots
A large container, at least 18 inches (45 cm) wide and deep, is a good way to keep comfrey from spreading in a small garden. Water regularly, as it is thirsty in a pot.
Companion planting
Comfrey is grown to feed other plants, as a mulch and compost source.
Good companions
- Tomato Comfrey mulch and liquid feed add potassium, which tomatoes need for fruit.
- Potato Comfrey leaves laid in the trench or used as mulch add nutrients.
- Fruit trees A patch at the edge of the drip line gives a ready supply of mulch, and the flowers draw bees.
- All plants (chop-and-drop mulch) Cut leaves can mulch almost any bed.
Pests and diseases
NC State reports no serious insect or disease issues.
Pests to watch for
- Slugs and snails Holes in the leaves, especially on young plants in damp weather.
Comfrey is rarely troubled by disease.
Common questions
Is comfrey safe to eat or drink as tea?
No. Comfrey contains pyrrolizidine alkaloids, and NC State notes that eating it can cause liver and lung damage and cancer. It is no longer considered safe for consumption; use it only for compost, mulch and fertilizer.
Will comfrey take over my garden?
It can. Common comfrey self seeds, and all comfrey regrows from small root pieces. Plant the sterile Russian comfrey Bocking 14, or grow it in a large container, and site it where it can stay.
How do I make comfrey fertilizer?
Pack cut leaves into a bucket, cover them with water and leave for at least a week. Dilute the dark liquid with water before using it on plants. It is high in potassium.
How often can I cut comfrey?
Several times a year once established. Cut a few inches above the ground and it regrows quickly.
How do I get rid of comfrey?
Dig out the plant and every piece of root you can find, then keep removing new shoots, as any root fragment can resprout.
Sources we checked: NC State Extension Gardener Plant Toolbox: Symphytum officinale; NC State Extension Gardener Plant Toolbox: Symphytum x uplandicum (Russian comfrey).
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