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Sisymbrium altissimum

tall tumblemustard

Brassicaceae Europe and western and central Asia

Overview

Sisymbrium altissimum is an annual or winter-annual herb in the mustard family (Brassicaceae), growing 1.5-5 feet (0.5-1.5 m) tall on a stout, branching stem. Lower leaves are large and deeply lobed, 2-8 inches (5-20 cm) long, while the upper leaves are divided into very narrow, thread-like segments. Small pale yellow flowers about 0.3 inch (6-9 mm) across, each with four petals, open in loose clusters at the stem tips from late spring into summer. They are followed by slender seed pods (siliques) 2-4 inches (5-10 cm) long that stand out from the stem. As the plant dries, it often breaks off at the base and tumbles in the wind, scattering seed across open ground. It germinates in fall or spring and colonizes disturbed soils, fields, roadsides, and rangeland. One limitation is its weediness: it spreads aggressively from abundant seed, competes with crops and rangeland, and is regulated as a noxious weed in some areas.

Native Range

Sisymbrium altissimum is native to Europe and western and central Asia and has naturalized across most of North America, including much of the United States and southern Canada. It grows in disturbed, open ground such as fields, roadsides, and rangeland.

Suggested Uses

Sisymbrium altissimum is not grown ornamentally and is managed as a weed of crops, rangeland, and disturbed ground. The young leaves and seeds have been eaten in some regions. In any planting it appears only as an unwanted colonizer of open soil.

How to Identify

A tall, branching mustard 1.5-5 feet (0.5-1.5 m) high has large, deeply lobed lower leaves and thread-like upper leaves. Pale yellow, four-petaled flowers about 0.3 inch (6-9 mm) wide are followed by slender seed pods 2-4 inches (5-10 cm) long that spread away from the stem. The narrow, divided upper leaves and the long, outward-pointing pods separate it from Sisymbrium officinale, which has pods pressed close to the stem.

Appearance

Size & Dimensions

Height1'6" - 5'

Width/Spread1' - 2'6"

Colors

Flower Colors

yellow

Foliage Colors

green

Fall Foliage Colors

no change

Bloom Information

Bloom Period

~12 weeks

Spring Summer

Flowering runs from late spring into summer, generally May to August. The small yellow flowers open in clusters at the branch tips over several weeks. Seed pods ripen through summer, after which the dried plant breaks free and tumbles.

Detailed Descriptions

Foliage Description

green

Growing Conditions

Sun Requirements

SunFull Sun

Requires 6-12 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range6.0 - 8.0(Neutral)

357912

Soil Types

sand loam clay rocky

Drainagewell drained

Water & Climate

Water Needs

Low

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Sisymbrium altissimum grows in full sun on dry, well-drained soils and tolerates poor, sandy, disturbed, and compacted ground. It germinates with fall or spring moisture and needs no care, behaving entirely as a weed of open land. It withstands heat and drought and finishes its cycle quickly in dry conditions. Dense cover crops, mulch, or established plantings shade the soil and limit its germination. It has few pests. Plants die after seeding and break loose to disperse seed widely.

Pruning

No pruning applies to this weed. Cutting or pulling plants before the seed pods ripen reduces spread, since a single plant releases thousands of seeds. Dried plants are removed before they break free and tumble.