Ministry of Agriculture, Food and Rural Affairs

Ontario Weeds: Yellow rocket

Table of Contents

1. Scientific name
2. Other names
3. Family
4. General description
5. Habitat
6. Stems
7. Leaves
8. Flowers and fruit
9. Often confused with / Distinguishing features
10. Herbicide resistance
11. References
12. For more information...

Scientific name:

Barbarea vulgaris

Other names:

Herb barbara, Herb of St. Barbara, Winter cress, barbarée vulgaire, herbe de Sainte-Barbe, cresson d'hiver

Family:

Mustard Family (Cruciferae) 

General description:

Usually biennial or perennial, but some plants flower, set seed and die after their first growing season; reproducing only by seed.

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 grain fields is increasing.

Stems:

• Stems form in the spring
• 1 to several stems per plant
• Stem is erect, 20 - 80 cm high

Leaves:

• Young plants produce a rosette of smooth, shiny, dark green leaves during the first year
  
• Leaves stay green throughout the winter and may turn slightly purple by spring
  
• Leaves are long-stalked, hairless and divided into one rounded terminal lobe with several smaller lobes along each side
  
• Upper leaves are alternate (one per node), short-stalked or stalkless
  
• Upper leaves are coarsely toothed (or without teeth), or sometimes deeply lobed but always with a pair of basal lobes which clasp the stem

Flowers & fruit:

• Flowers are golden-yellow and 10-16 mm across
• Seedpods and their stalks either nearly erect and overlapping one another forming a dense raceme
• Or the stalks spread with the seedpods standing outwards or curving upwards and usually not overlapping one another, forming an open raceme
• Stalks are usually 3-6 mm long, pods 1.5-3 cm long with a slender, seedless beak 2-3 mm long
• Seeds egg-shaped 1-1.5 mm long and a metallic gray-brown colour
• Flowers from mid-May to early July and sometimes again briefly in late autumn.
  

Often confused with / Distinguishing features:

Yellow rocket is often mistaken for wild mustard. 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.

Herbicide resistance

No documented cases of herbicide resistance to date.

References

http://www.weedinfo.ca/en/weed-index/view/id/BARVU
http://www.omafra.gov.on.ca/english/crops/facts/ontweeds/yellow_rocket.htm

Figure 1. Yellow rocket seedling

Figure 2. Leaf of yellow rocket with basal lobe clasping the stem

Figure 3. Flowers of yellow rocket

Figure 4. Yellow rocket whole plant