Yellow rocket, Barbarea vulgaris

Life Cycle

Usually biennial, or perennial

Propagation

Reproducing only by seed.

Stems

Stems forming in the spring, 1 to several stems per plant, erect, 20 - 80 cm high, branched; rosette and lower stem.

Leaves

Young plants produce a rosette of smooth, shiny, dark green leaves during the first year, these staying green throughout the winter or turning slightly purplish by spring. Long-stalked, hairless, divided into 1 large rounded terminal lobe and smaller lobes along each side. Upper leaves alternate (1 per node), short-stalked or stalkless, coarsely toothed, or without teeth, or sometimes deeply lobed, but always with a pair of basal lobes which clasp the stem.

Flowers and Fruit

Flowers are golden-yellow and 10-16mm across; the seedpods and their stalks either nearly erect and overlapping one another forming a dense raceme as in the typical botanical variety (B. vulgaris var. vulgaris), or as in the second botanical variety (B. vulgaris var. arcuata Opiz. Fries), the stalks spreading with the seedpods standing outwards or curving upwards and usually not overlapping one another, thus forming an open raceme; stalks 3-6mm long; pods 1.5-3cm long with a slender, seedless beak 2-3mm long; seeds egg-shaped 1-1.5mm long, metallic grayish-brown. Flowers from mid-May to early July and sometimes again briefly in late autumn.

Roots and Underground Structures

Root system on young plants a taproot, becoming much-branched and fibrous with age.

Habitat

Yellow rocket is common throughout most of Ontario in meadows, pastures, waste areas, roadsides, railways and along watercourses. It is especially common in moist rich soil and is apparently still spreading rapidly in such areas. Its occurrence in grainfields is increasing.

Distinguishing Features

It is similar to Wild mustard and often mistaken for it, although the two are easily distinguished. Yellow rocket is a perennial or biennial, so flowers much earlier in the season than Wild mustard and has smaller and deeper golden-yellow flowers. Its leaves are dark glossy green or somewhat purplish, hairless, and distinctly clasp the stem, and the seedpod is tipped by a very slender beak which does not have a seed in its base.

Species Benefits

Studies have shown that yellow rocket has great potential as a dead-end trap crop for improving management of P. xylostella, the diamondback moth, a significant insect pest of cruciferous crops. Lu, JH, Liu, SS., Shelton, AM. (2004) Laboratory evaluations of a wild crucifer Barbarea vulgaris as a management tool for the diamondback moth Plutella xylostella. Bull Entomol Res. 94(6):509-516.

Legislation

Noxious under the Ontario Weed Control Act.


Figure #1.

A. Base of plant. B. Flowering and fruiting stem of variety with spreading seedpods.


Figure #2.

Yellow Rocket Seedling.


Figure #3.

Leaf with basal lobes clasping stem.


Figure #4.

Flowering plant.


Figure #5.

Flowers of yellow rocket.


Figure #6.

Flowering plant.


Figure #7.

Leaf with basal lobes clasping stem.


Figure #8.

Leaf of yellow rocket.