Common Comfrey (Symphytum officinale) — identification, habitat & look-alikes

Common comfrey is a European herb long used in poultices for sprains, bruises, and broken bones. It has escaped from gardens in North America and grows wild along roadsides and in fields. It contains liver-damaging compounds, and in 2001 the FDA moved to remove comfrey products taken by mouth from the market. It is also called knitbone.

Appearance

Growth form: A coarse perennial usually about 2–3½ ft (60–105 cm) tall, sometimes up to 5 ft (1.5 m), with a deep taproot.
Leaves: Large, bristly, lance- to egg-shaped leaves up to 10 in (25 cm) long. The leaf bases run down the stem, giving it strong wings.
Flowers: Nodding bell-shaped flowers about ½ in (1.3 cm) long, in cream, pink, or purple, in coiled clusters that unroll as they open.
Flowering time: May to August in Minnesota.
Fruit: Each flower makes four shiny black .

Look-alikes

Russian comfreySymphytum × uplandicum

Russian comfrey has stems without wings, leaves that don't run down the stem, bluer or violet flowers, and dull rather than shiny seeds. It also blooms later (June–August).

Why they get mixed upIt is a hybrid of common comfrey and looks much like it.

Northern bluebellsMertensia paniculata

Bluebells have blue flowers with flat-lying hairs on the calyx and grow in woods and forest edges. Common comfrey has pink to purplish flowers with spreading calyx hairs and grows in sunnier, disturbed spots.

Why they get mixed upIt is a native relative in the same family, with similar nodding bell flowers.

FoxgloveDigitalis purpurea

Foxglove flowers are spotted inside and line a tall spike. Without flowers, the leaves are hard to tell apart. Foxglove is a deadly heart poison.

Why they get mixed upBefore blooming, its leaves look like comfrey's, and people have died after mistaking it for comfrey.

Where it lives

Typical habitats: Roadsides
Fields
Waste places
Gardens
Range: Native to Europe and western Asia. In the US it is an introduced weed that spreads from gardens; in Minnesota, for example, it is scattered and likely under-reported, often near places where it was sold as nursery stock.
Preferred conditions: Grows in sun to part shade on average to moist, disturbed soil. In its native range it grows in damp grassland and along riverbanks.
Flowering: Flowers May–Aug
Flowers May–Aug

Cautions

Cautions: Contains , which can damage the liver. Do not eat it or drink it as tea. In 2001 the FDA and FTC acted against comfrey products meant to be taken internally or used on open wounds.

Name and classification

About the name: Russian comfrey (Symphytum × uplandicum) is a hybrid of common comfrey and rough comfrey (Symphytum asperum), and is also sold simply as "comfrey."