Pest Profile

• Weed Description: Blue mustard invades disturbed habitats and cultivated lands, reducing crop yields and affecting crop quality (Whitson et al. 1996). It is a problem in winter annual crops, such as winter wheat (Klein et al. 1985). Blue mustard gives off a disagreeable odor (like stale dishrags), and dairy animals eating it may produce off-flavor milk.
• Leaves:  Leaves are alternate and oblanceolate, with wavy or coarsely toothed margins, and are partially covered with minute, gland-tipped hairs.
• Stems: Mature plants are 10–50 cm tall, with branches that spread mainly from the base. Stems are partially covered with minute, gland-tipped hairs.
• Flowers:  Flowers are small and bluish purple, have 4 petals, and are connected by a stalk to a rough central stem.
• Fruit: Fruits have a conspicuous beak, about one third the length of the pod. These fruits break apart transversely into numerous 2- seeded sections instead of splitting longitudinally as with most mustards.
• Seeds: Seeds are rectangular, with one flat side and one rounded side (Stubbendieck et al. 1995).
• Identifying Characteristics: Blue mustard is commonly found in dry areas such as grain fields, along roadsides, rights-of-way, and disturbed habitats. It can tolerate a wide range of environmental conditions and soils.

(Cited from 'A Guide to Weeds in British Columbia')