Field Peppergrass

Mustard (Brassicaceae family)

Lepidium campestre (L.) W.T. Aiton

EPPO code:

LEPCA

Other names:

Field pepperweed, pepperweed

Species information

Lifecycle:

Annual or winter annual.

Propagation:

Reproduces by seed.

Emergence:

Typically, field peppergrass germinates and emerges in the fall or early part of spring.

Habitat:

Field peppergrass is predominately found in orchards, nurseries and waste areas in southern Ontario. It is rarely found in cultivated fields.

Competitiveness:

Little published data exists and results are varied. Swan (1971) indicated yield losses in winter wheat as high as 45%, while more recently a Swedish study evaluating peppergrass as an oil crop observed increased Barley yields when field peppergrass was under-seeded (Merker et al., 2010)

Identification clues

Seedling

Cotyledons:

Club-shaped to oval, with a long stalk, 12–15 mm long.

Young leaves:

The plant’s first leaves emerge as a basal rosette, oval with entire margins and on long petioles.

Mature leaves:

Rosette leaves become wavy-toothed to deeply-lobed margins. The stem leaves are alternate, arrow shaped and clasp the stem. Margins are entire to slightly toothed.

Mature plant

Stem:

The stem is erect, grows 10–60 cm tall and has short hairs. It is much branched near the top.

Flowers:

Field peppergrass produces clusters of small, white four-petal flowers.

Fruit:

Seedpods are numerous, flat and round. The top of the seedpod has a small notch; each contains two small, rust-coloured to brown seeds.

Roots:

Taproot.

Often mistaken for

I know it's not Stinkweed because stinkweed is hairless as compared to the rough-textured field peppergrass that is densely hairy. Field peppergrass does not produce an odour when plant tissue is crushed.