Weeds Identification Gallery

Fivehook Bassia

  • Bassia hyssopifolia
  • Mustard Family: Brassicaceae
Updated: 09/2025

Fivehook bassia, a summer annual broadleaf, is an important weed found most frequently on saline soils. It germinates in early spring and the plant matures in late summer. It is found throughout California except the northwestern region and high elevations in the Sierra Nevada up to 4000 feet (1200 m) elevation. Fivehook bassia inhabits agricultural land (especially newly cultivated cropland) and disturbed and moist places. Although considered to be fair sheep forage, its leaves have varying amounts of potassium oxalate and can be fatal to livestock when large amounts are consumed.

Habitat

Roadsides, disturbed places, crop fields, ditchbanks, and seasonal wetlands.

Several stems with lance-shaped, slender, gray-green leaves against the darker soil background. Copyright information is at the bottom (Copyright 2007 The Regents of the University of California. All rights reserved.). Credit: Joseph M. DiTomaso, UC Agriculture and Natural Resources
Leaves. Credit: Joseph M. DiTomaso, UC Agriculture and Natural Resources

Seedling

Fivehook bassia seedlings are indistinguishable from Kochia seedlings. Both have linear to narrowly lance-shaped, gray-green cotyledons (seed leaves) with soft white hairs. Subsequent leaves are narrowly lance shaped and similar in size to the cotyledons.

Seedlings showing thick, long, grayish leaves with soft hairs growing in rosette form, S; Siskiyou Co., . Credit: Jack Kelly Clark, UC IPM
Seedlings. Credit: Jack Kelly Clark, UC IPM

Young Plant

Leaves on very young plants form a rosette.

Mature Plant

The mature plant can reach 4 feet (1.2 m) tall. Several stems branch from the main stem, however, fivehook bassia it is not as branched as another member of the family, Russian thistle. Leaves are linear-lance shaped to lance shaped, slender, generally gray green, and flat. They mostly are alternate to one another along the stem and are covered with soft hairs. Fivehook bassia is hairier than kochia.

Mature plant, single main stem, small leaves Klamath Co., OR; Credit: Jack Kelly Clark, UC IPM
Mature plant. Credit: Jack Kelly Clark, UC IPM

Flowers

Flowers bloom from July through October. Flowering stems form spike flower heads along which inconspicuous flowers develop in clusters at the bases of leaf stalks and at the ends of the stems. Individual flowers do not have petals, but they have outer lobes that are densely covered with tan to golden, soft, furry hairs. A yellowish, tiny, hooked or curved spine is attached to the back of each lobe.

At the end of a stem, tiny clusters of reddish orange flowers form at the bases of leaf stalks against a black background. Copyright information is at the bottom (Copyright 2007 The Regents of the University of California. All rights reserved.). Credit: Joseph M. DiTomaso, UC Agriculture and Natural Resources
Flowers. Credit: Joseph M. DiTomaso, UC Agriculture and Natural Resources

Fruits

Fruits remain enclosed within the dried flower. They are thin walled and have five, hooked spine lobes (one hook attached to each lobe).

Seed

There is one seed per fruit. Seeds are egg shaped and about 1/25 to 2/25 of an inch (1–2 mm) long.

Four egg-shaped seeds surrounded by the five-hooked fruit they came from against a grey background. Copyright information is at the bottom (Copyright 2007 The Regents of the University of California. All rights reserved.). Credit: James A. O'Brien, University of California
Seeds. Credit: James A. O'Brien, University of California

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