Hirschfeldia spp.

summer mustard

Mediterranean Basin and North Africa

Attracts Pollinators Attracts Butterflies Drought Tolerant

Overview

Hirschfeldia spp. is a small genus in the mustard family (Brassicaceae), represented chiefly by H. incana, known as summer mustard, shortpod mustard, or Mediterranean mustard. A fast-growing annual to short-lived perennial, it begins as a flat rosette of lobed, roughly hairy grey-green leaves, then sends up a wiry, branched flowering stem 1-6 feet (0.3-1.8 m) tall. Small four-petalled yellow flowers about 0.25-0.4 inch (6-10 mm) across open in slender clusters over a long season, followed by short pods pressed close to the stem, each tipped with a stout beak holding a single seed. Native to the Mediterranean Basin and North Africa, Hirschfeldia spp. has spread to dry, disturbed, and roadside ground in mild climates worldwide. It is an aggressive colonizer of bare soil and is listed as an invasive weed in California and other parts of western North America, where it crowds out native annuals. The plant resprouts from a deep taproot after cutting, which makes it persistent in disturbed sites.

Native Range

Hirschfeldia spp. is native to the Mediterranean Basin and North Africa. H. incana has naturalized as a weed across western North America, South America, Australia, and other mild-climate regions, especially on roadsides and disturbed land.

Suggested Uses

Hirschfeldia spp. is rarely grown on purpose; it appears mainly as a wild and roadside plant and a colonizer of disturbed ground. The flowers are an early nectar source for bees and other insects in waste areas. In managed landscapes it is treated as a weed to be removed rather than a planting.

How to Identify

Recognized by a basal rosette of lobed, bristly grey-green leaves and a tall, wiry branched stem carrying small yellow four-petalled flowers and short seed pods held tight against the stem, each pod ending in a flattened beak. The beaked, appressed pods separate Hirschfeldia spp. from related field mustards (Brassica spp. and Sinapis spp.), whose pods spread outward.

Appearance

Size & Dimensions

Height1' - 6'

Width/Spread8" - 2'

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~16 weeks

Spring Summer Fall

Hirschfeldia spp. flowers over a long season from spring into autumn, and nearly year-round in mild coastal climates. The small yellow flowers open in clusters as the branched stem lengthens. Seed sets continuously behind the flowers, and a single plant can produce thousands of seeds.

Detailed Descriptions

Foliage Description

grey-green, roughly hairy

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

loam sand clay

Drainageaverage

Water & Climate

Water Needs

Low

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Hirschfeldia spp. needs no cultivation and grows in full sun on poor, dry, compacted, and disturbed soils with a pH around 6.0-8.0. It is drought-tolerant once the deep taproot forms and tolerates heat and neglect. Because it self-seeds heavily and resprouts from the taproot, control means removing plants with the root before the pods ripen, or repeated cutting to exhaust the crown. It is rarely planted deliberately and is managed as a weed in most regions. Seedlings emerge after autumn and winter rains. Dense stands shade out smaller native plants.

Pruning

Cutting or mowing before the pods ripen reduces seed set, but the plant resprouts from its deep taproot and usually needs the root removed for lasting control. Repeated cutting through the season gradually weakens the crown. No ornamental pruning applies.