Stems & Roots: Stems erect,
10-60cm (4-24in.) high, lower part with short, downward-pointing
Leaves: Alternate (1 per node), often
in a dense rosette in late autumn and early spring, dark green
to blackish-green, oblong in general outline, pinnately cut or
divided into coarsely lobed segments, the bottoms of the spaces
between segments more or less rounded.
Flowers & Fruit: Flowers similar
mustard but pale yellow, the lowermost several flowers and
pods of each raceme in axils of small leaves; seedpods 2-5cm (4/5-2in.)
long, with a narrow beak about 3mm (1/8in.) long, on slender stalks,
pointing outwards and upwards; seeds oval, reddish-brown, about
1.2mm (1/20in.). Flowers from late May to late fall.
Habitat: Dog mustard occurs throughout
Ontario but is more common in the south. It is frequently found
around railway yards, waste places, orchards, gardens, roadsides
and occasionally in grainfields.
Similar Species: It is distinguished
from most other plants of the Mustard Family in Ontario by having
several of its lowermost flowers and seedpods in the axils of
small leaves. Only Garlic mustard also has this characteristic.
Rosettes of young plants resemble Tumble mustard but Dog mustard
leaves are usually darker in colour, the segments are broader
and more coarsely lobed, and the tips of the lobes are usually
rounded in Dog mustard but somewhat sharp-pointed in Tumble mustard.