Wild mustard.

At a glance

Care level

Easy

Plant type

Annual herb

Light

Full sun

Indoor light

Direct sun

Water

Every 3 to 7 days

Mature size

2 to 3 feet

Growth rate

Fast

Hardiness

USDA 3 to 9

Bloom time

Late spring to mid summer

Care

Give this plant plenty of sunshine and keep the soil consistently moist but not waterlogged. Watch for yellowing leaves which can indicate overwatering or poor drainage. It is a vigorous grower so keep an eye on it to ensure it does not crowd out other plants.

Watering

Keep the soil evenly moist but allow the top inch to dry out slightly between waterings.

Feeding

A balanced liquid fertilizer applied monthly during the growing season is plenty.

Pruning

Deadhead spent flowers regularly to encourage more blooms and prevent unwanted seed spread.

Repotting

As an annual, you typically do not need to repot this plant, but you can refresh the soil if growing in containers.

Soil

Well draining loamy soil

Soil pH

6.0 to 7.5

Temperature

-10 to 35°C

Humidity

40 to 70%

Safety

People

The plant is generally considered non-toxic, but the seeds contain mustard oils that may cause irritation if consumed in excess.

Pets

This plant can be toxic to pets if ingested in large quantities due to glucosinolates.

Children

The seeds are small and could pose a choking hazard if ingested by small children.

Contact allergens

Handling the stems or leaves may cause mild skin irritation in sensitive individuals due to fine hairs.

Airborne allergens

Pollen from this plant can trigger hay fever symptoms in susceptible people during the peak flowering season.

Edibility

While the leaves are edible when young, the seeds contain compounds that can be irritating in large quantities.

How to identify it

• Bright yellow four petaled flowers
• Roughly hairy stems and leaves
• Lower leaves are deeply lobed
• Upper leaves are lance shaped
• Long slender seed pods

Height

0.2 to 0.8m

Spread

0.15 to 0.3m

Leaves

green, deciduous

Flowers

yellow, 1 to 2cm

Fruit

brown, Late summer

Problems to watch for

• Downy mildew · Appears as yellow patches on leaves during cool, damp weather.
• Flea beetles · Small beetles that chew tiny holes in the foliage.

Growing it

Propagation

seed

When to plant

spring

Plant this in areas where you want to attract pollinators to your vegetable garden.

Grows well with

• Peas · They grow well together as they have similar light and moisture requirements.
• Clover · Clover enjoys the same open, sunny ground, and both plants attract pollinators.

Similar species

• Black Mustard · It has a similar appearance and yellow flowers but grows much taller.

Science

Family

Brassicaceae

Genus

Sinapis

Order

Brassicales

Class

Magnoliopsida

Native range

Europe, Western Asia, and North Africa.

Conservation

This species is considered a widespread agricultural weed and is not of conservation concern.

It thrives in disturbed soils and open fields where it can quickly outcompete other annuals for sunlight.

Value to wildlife

early season nectar source, supports beneficial insects

Pollinators

bees, butterflies, beetles

Uses

cover crop, pollinator habitat, culinary greens

Taxonomy resolved against GBIF.

Questions people ask

Is this plant invasive?

It is considered a weed in many agricultural settings, though it is native to Europe and parts of Asia.

Can I eat the leaves?

Yes, young leaves are edible and have a peppery flavor similar to arugula.

Where the name comes from

The genus name Sinapis is the Latin word for mustard, while the specific epithet arvensis means of the field.

Good to know

• It is a member of the Brassicaceae family, related to common mustard and cabbage.
• The seeds can remain viable in the soil for several years.
• It is closely related to white mustard, which is widely sown as a green manure, but wild mustard itself is usually treated as a weed.

Also in

• Plants toxic to cats and dogs