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Comfrey

Herbaceous Perennial Flower, Herb

Also known as Common Comfrey, Blackwort, Boneset, Healing Herb
Symphytum officinale
Boraginaceae Family

This coarse, spreading, perennial herb grows up to 4 feet tall and likes moist, somewhat shady locations. It has a long history as a medicinal herb but no culinary uses. Other species in this genus are more suited to ornamental plantings outside of the herb garden.

	Site and Plant Characteristics
	Growing Information
	Varieties

Site Characteristics

Sunlight:

full sun
part shade

Prefers shade in warm areas.

Hardiness zones:

3 to 9

Some of the related species or ornamental comfreys are only hardy to Zone 5.

Plant Traits

Lifecycle: perennial

Ease-of-care: easy

Height: 1 to 5 feet

Spread: 2 to 6 feet

Bloom time:

late spring
early summer

Flower color:

yellow
violet
white
pink

Ranges from purple-violet to pink, and creamy yellow to white.

Foliage color: dark green

Foliage texture: coarse

Shape: spreading mass

Shape in flower: same as above

Special Considerations

Special characteristics:

aggressive - Freely self-sows. Deep root system is difficult to eradicate. Even small fragments produce new plants.
non-invasive
not native to North America - Native to Europe, naturalized in North America.

Growing Information

How to plant:

Propagate by seed, division or separation - Plants are aggressive and readily self-sow. Plant seeds where you want them to grow in spring or fall, or sow in a cold frame and pot seedlings to be grown over the first winter inside.
Divide any time (spring is best) using a spade to chop off about 3 inches of root just below soil level. Plant divisions directly or pot them and overwinter before planting.

Maintenance and care:

Plants are very aggressive. Plant where they can spread without competing with other plants, or rein them in with a physical barrier.
Remove flowers to keep foliage looking nice. Deadhead plants to keep from spreading by seed.
More growing information: How to Grow Perennials

Diseases:

Leaf spot

Varieties

Some related species of ornamental value include:
Caucasian comfrey (S. caucasicum) grows 2 feet tall and bears bright blue flowers in spring. Spreads aggressively. Zones 3-9.
Large-flowered comfrey (S. grandiflorum, S. ibericum) grows 1 to 1.5 feet tall and bears yellow flowers in spring. Spreads aggressively. Zones 5 to 9. (Some sources say hardy to Zone 3.) 'Variegatum' ('Goldsmith') has creamy margins and blue, cream or pink flowers.
Russian comfrey (S. x uplandicum) is a cross between S. asperum and S. officinale. It grows up to 6 feet tall and bears purple-blue flowers in late spring or early summer. Zones 4 to 8. (Some sources say hardy to Zone 3.) 'Variegatum' grows 3 feet tall, has gray-green leaves with creamy margins, and bears pale lilac blue to pink flowers.