Common dogmustard (Erucastrum gallicum)

Synonyms: Sisymbrium gallicum, Brassica erucastrum, Brassica ochroleuca

Common Names: Dog mustard, dog-mustard, French rocket, rocketweed

Description:

Common dogmustard (Erucastrum gallicum) is a weedy annual or biennial in the mustard family, native to Europe and introduced to North America in the early 1900s [1][2]. It grows on disturbed, open ground ? farm fields, roadsides, railroad edges, and waste places ? and is best known as a weed of grain and other crops [1]. MISIN tracks it because it spreads readily by seed across disturbed soil, though it is not a plant of healthy natural areas [1][2].

Habit:

Common dogmustard is an upright, branching plant about 1 to 2 feet tall with pale yellow, four-petaled flowers ? the classic cross shape of the mustard family [1][2]. Its leaves are deeply cut into several narrow lobes on each side (pinnately lobed), the largest leaves near the base and smaller ones up the stem; the leaves and stems are roughly hairy with stiff, curved white hairs [1]. A helpful tell is the flower cluster: small leaf-like bracts are scattered among the lower flowers, which most other roadside mustards lack [2]. The seed pods are slender, smooth, four-sided, about ? to 1? inches long, and angle upward along the stem [1].

It is easiest to spot from early summer into fall (about June through September), when the loose clusters of pale yellow flowers and the upward-angled pods are present together on disturbed ground [1]. Look for it on tilled fields, gravelly roadsides, and railroad ballast rather than in shaded woods or undisturbed prairie [1][2].

At-a-glance cues:

1. Pale yellow, four-petaled mustard flowers in loose, lengthening clusters [1][2]
2. Deeply lobed leaves with stiff, curved white hairs on leaves and stems [1]
3. Small leaf-like bracts scattered among the lower flowers [2]
4. Slender, smooth, four-sided seed pods angling upward along the stem [1]

Leaves:

1. Arrangement: alternate; largest in a basal cluster, becoming smaller up the stem [1][2]
2. Shape: oblong to widest near the tip in outline, deeply pinnately lobed with 3?10 narrow lobes per side [1]
3. Margin: lobes shallowly toothed with rounded or angled tips [1]
4. Size: basal and lower leaves about 1?11 inches long [1]
5. Surface: sparsely to moderately covered with stiff, curved, white hairs [1]

Stems:

1. Habit: erect to ascending herbaceous stems, branched or unbranched, about 1?2 feet tall [1][2]
2. Surface: green, roughened by stiff, curved, white hairs pressed against the stem [1]
3. Life cycle: a non-woody annual or biennial [1][2]

Flowers:

1. Color: pale yellow to nearly white [1][2]
2. Shape: four petals in a cross (typical of the mustard family), each flower about ? to ? inch across, with narrow erect sepals [1]
3. Arrangement: in loose clusters that lengthen as they bloom, with small leaf-like bracts among the lower flowers [1][2]
4. Bloom time: early summer into fall, about June through September [1]

Fruit and seeds:

1. Fruit type: a slender, smooth, four-sided pod (silique) about ? to 1? inches long, with a short beak at the tip [1]
2. Orientation: pods angle upward along the stem, straight to slightly curved [1]
3. Seeds: reddish-brown, about 1?1.5 mm long, with a faint honeycomb texture, in a single row per pod [1]
4. Dispersal: by seed, which moves in soil, crop seed, and on equipment working disturbed ground [1]

Habitat:

Common dogmustard is native to Europe and was introduced to North America in the early 1900s [1][2]. It is a plant of disturbed, open ground rather than intact natural habitat [1][2].

It grows in full sun to part shade on disturbed soils ? cultivated fields, roadsides, railroad edges, gravel pits, and waste areas [1]. It is most common where soil is regularly turned or bare, which is why it shows up as a weed of crop fields and other worked ground [1][2].

Reproduction:

Common dogmustard spreads entirely by seed. Each plant forms many slender pods, and the small reddish-brown seeds move in soil, in crop and grass seed, and on tires and farm equipment working disturbed ground ? which is how it travels from field to field and along roads and rail lines [1]. It does not spread by runners or creeping roots, so a patch grows from seed dropped nearby or carried in [1].

It is a fast annual or biennial: plants sprout from seed, grow up, flower from early summer into fall, and set seed in the same or the following season [1][2]. For control, the key is to remove plants before the upward-angled pods ripen and shed seed, since seed is the only way it spreads [1].

Impact and Damage:

For homeowners, common dogmustard is a minor nuisance weed rather than a hazard. It is not known to be toxic or to irritate skin, and it turns up mainly on disturbed ground ? garden edges, driveways, and recently cleared or tilled soil ? where it competes with other plants for space and moisture [1][2]. It does not damage structures or form lasting underground systems, so individual plants are easy to remove [1].

For natural area stewards and growers, common dogmustard is best known as an agricultural weed of crop fields and other worked ground, where it competes with crops [1]. It is a plant of disturbed soil and does not typically invade healthy, undisturbed natural plant communities, so it is a lower-level concern than aggressive habitat invaders [1][2]. Keeping soil covered and removing plants before they seed limits its spread on a property [1].

Similar species:

Common dogmustard is one of several weedy yellow mustards of disturbed ground, and they are easy to mix up. The surest checks are its pale yellow flowers, its deeply lobed and stiffly hairy leaves, the small leaf-like bracts among its lower flowers, and its upward-angled pods [1][2].

Loesel's mustard (Sisymbrium loeselii) is a closely similar weedy mustard. It is told apart by its flower cluster, which lacks the small leaf-like bracts that dogmustard scatters among its lower flowers, and by fine differences in the seed pods [2].

Wild mustard (Sinapis arvensis) is a very common yellow mustard of fields and roadsides. It is distinguished by its brighter, deeper yellow flowers and its pods that tend to spread out from the stem, while common dogmustard has paler flowers and pods that angle upward, plus the small leaf-like bracts among its lower flowers [1].

Monitoring and rapid response:

Signs to watch for:

1. Upright, branching plants 1?2 feet tall with pale yellow four-petaled flowers on disturbed ground ? most visible early summer into fall [1][2]
2. Deeply lobed, stiffly hairy leaves and small leaf-like bracts scattered among the lower flowers [1][2]
3. Slender, four-sided seed pods angling upward along the stem, a sign seed is forming [1]

What you can do:

1. Hand-pull or hoe plants while young and before the pods ripen ? the shallow roots come up easily, especially in moist soil [1]
2. Bag and remove plants that already have pods rather than composting them, since seed is the only way it spreads [1]
3. Keep disturbed soil mulched or planted so seeds have less open ground to colonize, and clean soil and seed off equipment moving between sites [1]
4. Catch and pull new plants over the season; repeating this before seed-set draws down the seed in the soil [1]
5. For natural areas and field edges, crews can focus on disturbed ground and outlying patches, pulling or mowing plants before the pods ripen and revisiting to catch new seedlings [1][2]

When to call a professional:

1. Large or recurring infestations across crop fields or worked ground where hand removal cannot keep up [1]
2. Situations where a persistent seed bank keeps producing new plants season after season despite removal [1]
3. For chemical control options, contact a licensed applicator or your local cooperative extension office.

Report sightings to MISIN. Help track this species' spread by submitting observations through the MISIN web site or the MISIN mobile app (Android, iOS, Windows, and macOS). Photos at multiple angles paired with a precise GPS location are the most valuable data for confirming new occurrences and triggering rapid-response review.

Credits:

1. Minnesota Wildflowers. Erucastrum gallicum (Dog Mustard). minnesotawildflowers.info
2. Native Plant Trust, Go Botany. Erucastrum gallicum (common dog-mustard). gobotany.nativeplanttrust.org

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