Sweet woodruff

Photo: Krzysztof Ziarnek, Kenraiz — CC BY-SA 4.0 · source

Survives zone 4 through 8

Harvest calendar

Ripens: Leaves cut just before flowering in spring, for the strongest scent once dried

Best planted in early spring after your last frost, or in fall before the ground freezes, depending on your climate.

The fragrance is barely there in the fresh leaf and develops only once cut and dried, as the coumarin compound responsible is released by wilting — the classic use is Germany's May wine (Maiwein), where dried sprigs are steeped in young white wine. Large quantities of coumarin are best avoided; this is a flavoring herb used in modest amounts, not a leafy green.

Hardiness

Zone 4–8

Habit

Groundcover

Edible part

Leaf

Ripens

Leaves cut just before flowering in spring, for the strongest scent once dried

Mature size

Low, creeping groundcover to about 20–30 cm

Light

Full shade to part shade

Soil pH

6.0–7.5, prefers calcareous soil

Environment

Temperate woodland

Native range

Temperate Eurasia, from Spain and Ireland to Japan, and Algeria — shaded and humid woodland.

Status

Both wild and cultivated

Years to fruit

1 yr

Growth speed

Moderate to fast — spreads steadily by rhizome once settled, and can become a nuisance

Spacing

25 cm (10 in) apart — about 16 per m² (15 per 10 sq ft)

Leaf shape

Narrow, lance-shaped leaves in neat whorls of six to nine around a square stem — the ruff-like whorl is the identification point, and no other woodland groundcover of its size does it.

Root system

Shallow, thin, wiry rhizomes running just under the leaf litter, forming a dense mat. Nothing deep — it competes poorly in drought but colonises dry shade under trees better than almost anything else.

Fruit description

Not a food: small dry burred fruits about 2 mm, covered in hooked bristles that catch on fur and clothing. ⚠ The plant's coumarin is what gives the dried herb its scent, and it is also why sweet woodruff should be used in modest amounts — large or prolonged doses are not safe.

Propagation

Division of the creeping rhizomes in spring or autumn, or seed.

Pollination

Insect-pollinated, and largely beside the point: the plant spreads by rhizome and is grown from division. Seed sets sparsely and germinates slowly.

The edible parts listed above are a starting point, not a field guide. Identify a plant with certainty — ideally against a local authority — before eating any part of it, and read the full disclaimer. Spotted something wrong? Report it.