Canola, Volunteer (Brassica campestris, Brassica napus)

Canola, Volunteer description

Erect, hairless, emerging from rosettes, average of 8 in Polish varieties; average of 5 in Argentine varieties. Polish varieties 20 to 50 inches tall, when mature. Argentine varieties 30 to 70 inches and the main stem more distinct.

Stem leaves of the two species are alternate, lanceolate, stalkless, with lobes where the leaves clasp the stems. Leaves fully clasping in Polish varieties, partially clasping in Argentine varieties.

Propagation

A volunteer is a canola plant that has grown from the seed of the previous crop or that has been introduced to the field through equipment, wind or other means.

Similar species

Wild mustard can be distinguished from volunteer canola by its' read-purple coloring on the stems at leaf axils, and by its' hairy stems.

Distribution

Volunteer canola can be a problem weed wherever canola is grown.

Identifying Canola, Volunteer

Seedling

Cotyledons of both species are broad, heart-shaped, indented at the tips. Leaves of Polish varieties are wrinkled and spiny underneath, yellow-green, growing in rosettes of 3 to 5 leaves. Leaves of Argentine varieties are smooth, blue-green, waxy, in larger rosettes of up to 6 leaves.

Root structure description

Taproot in both species.

Flowers

Yellow, with 4 petals, in both species. Flowers of Polish varieties with dark yellow, small flowers, in compact clusters, opening from the top of the stem to the bottom. Argentine canola flowers less clustered, with longer stalks, opening from bottom of the stem, upwards. Argentine canola has fewer pods, which shatter readily, containing larger seeds than Polish. Seed pods of Polish varieties are resistant to shattering, shorter and smaller, with longer beaks than Argentine varieties.