Tumble mustard

Common Name(s)

Tumble mustard

Tall mustard

Scientific Name

Sisymbrium altissimum

Family

Mustard family (Brassicaceae)

Reasons for concern

This plant spreads easily because it will break off at ground level and tumble across the landscape, scattering seeds for miles. It has rapid seedling growth and quickly takes over a habitat of native plants, reducing plant diversity so important to wildlife and pollinators.

Classification

Non-native

Botanical description

Tall, spindly herbaceous plant with large lobed leaves at the base and small yellow flowers on branching stems.

Leaves

Lower leaves are larger, course and divided into broad lobes. Upper leaves gradually become much smaller and finer with shallow lobes and alternate along the stem. Seedling rosette has deeply lobed leaves.

Stem(s)

Stems simple below, but much-branched above, giving a bushy appearance. Dead stems persist through fall. A single stem grows from the base leaves (rosette), reaching as high as 2 to 5 feet.

Flowers

Small, pale yellow, fading to white, arranged in clusters at the tips of stems. Blooms April to September.

Seeds

In a very slender capsule 2 to 4 inches long. A single plant can produce over a million seeds.

Roots

Slender, often branched taproot, with fibrous lateral roots.

Native to

Europe

Where it grows

Roadsides, fields, waste areas, and disturbed soils at elevations of 3,000 to 8,000 feet.

Lifecycle

Annual.

Reproduction

By seed

Weedy Characteristics

Tumble mustard is a prolific seed producer, producing up to a million seeds per plant. Its seeds survive up to 10 years in soil. Tumble mustard establishes quickly after fire.

Control Strategies

Remove rosettes before they form stems; plants can be more easily removed when small. Step down any disturbed soil. Never let them go to seed. Bag flowers and seeds, if they have developed. Broadleaf-selective herbicides work on young plants for large infestations.

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