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Treacle Mustard

Erysimum cheiranthoides (er-RIS-ih-mum kair-anth-OY-dees)

Family: Brassicaceae Non-native

Wormseed Wallflower is an annual or biennial in the mustard family. Its common name refers to its former use as an anthelmintic, a remedy to expel worms from the digestive tract. It differs from other species in the mustard family as it does not have the lobes and teeth that the other species are present. Its narrow leaves also set them aside from the mustard family. It is frequented by bees, flies and beetles, while other wildlife find the seeds and foliage quite bitter to the taste. However, if there is a limited food source, other wildlife may use this plant as a last resort. The upper half of the plant has few to no branches while numerous leaves form along the entire stem. The leaves are narrow, and the base tapers to a short petiole. Its flowers take the form of a raceme at the very top of the stem. The yellow flowers have 4 petals, 4 light green sepals, 6 stamens and a pistil. The tiny flowers can be hidden by the seedpods. Blooming from late spring into the later part of the summer, a colony can be in bloom for up to 2 months. It prefers a fertile loamy soil and full sun to perform at its best, however, will also flourish in sandy or clay based soil. Insects, Diseases, and Other Plant Problems: It can be quite weedy especially in disturbed areas such as pastures, roadsides, along railroad tracks and other waste areas.

Source: NC State Extension Gardener Plant Toolbox ↗ NC State Extension Gardener Plant Toolbox, 57 attributes.

How it fits the guild

Optimal soil pH Alkaline (>8.0); Neutral (6.0-8.0)
See companions & conflicts ↓

Companions & Conflicts

Curated pairwise relationships between this plant and others in the library — who feeds whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.

No curated interactions recorded for this species yet.

Also noted by NC State

Related species the NC State Plant Toolbox flags for this plant — look-alikes to tell apart, and plants that play a similar role in a planting. Ones we carry in the library are linked.

Full plant profile

Growing Conditions
Plant type
Annual; Weed
Life cycle
Annual; Biennial
USDA zones
4a, 4b, 5a, 5b, 6a, 6b, 7a, 8a, 8b
Light
Full sun (6 or more hours of direct sunlight a day) | Partial Shade (Direct sunlight only part of the day, 2-6 hours)
Soil texture
Clay; Loam (Silt); Sand
Soil pH
Alkaline (>8.0); Neutral (6.0-8.0)
Soil drainage
Moist
Available space
Less than 12 inches
Growth rate
Rapid
Maintenance
High
Form & Appearance
Habit / form
Ascending; Erect; Spreading
Texture
Medium
Leaf color
Green
Leaf type
Simple
Leaf arrangement
Alternate
Leaf shape
Elliptical; Lanceolate
Leaf margin
Dentate; Entire
Leaf size
3-6 inches long, < 1 inch wide
Hairs present
Yes
Leaf detail
The leaves have little or no stalk. The surface of the leaves have tiny star-shaped hairs. The leaves become smaller as they ascend the stem. The basal leaves will wither as the plant flowers.
Flower color
Gold/Yellow
Flower form
Raceme
Flower shape
Star
Flower size
< 1 inch
Flower detail
The flowers are formed as rounded clusters of 1/2", 4 petaled yellow flowers bloom in the summer at the top of the plant and the tips of the stems. Each flower will have 6 stamens, of which 2 are shorter than the other 4.
Bloom time
Spring; Summer
Fruit type
Siliqua
Fruit size
< 1 inch long, < 1 inch wide
Fruit detail
The fruit is a slender pod that contains a single row of seeds. The pod will split open when ripe.
Stem color
Green
Stem detail
The ribbed stems will elongate as the plant matures. The flowers form at the top of the stems, while its fruits will form below.
Wildlife & Ecology
Native status
Non-native
Origin
Europe, Japan
Wildlife value
Bees, beetles, and flies frequent are frequent visitors.
Attracts
Bees
Play value
Attracts Pollinators; Easy to Grow
Food & Medicine
Harvest time
Fall; Summer
Fruit type
Siliqua

Uses (ethnobotany)

Wildflower

Landscape Use
Landscape location
Meadow; Naturalized Area
Design feature
Mass Planting
Garden tags
#disturbed areas #problem for horses #acidic soils intolerant #frost tender #beetle friendly #fly friendly #self-seeding #bee friendly #weedy #poor soil tolerant
Problems & Resistance
Problems
Problem for Horses; Weedy
Resistant to
Poor Soil
Propagation
Seed

Planted at Hunnicutt

Nobody’s planted this one yet.