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Field guide
Russian thistle (Salsola tragus)
Forest & Kim Starr · CC BY 3.0

also Tumbleweed

Russian thistle

Salsola tragus

Family:
Amaranthaceae
Elevation:
1,000 ft – 7,500 ft
Bloom:
Jun – Oct
Region:
Southwest

Non-native invasive. This plant spreads aggressively and displaces native flora — it's here so you can recognize and manage it, not plant it. See Common problems & fixes below for removal guidance.

A bushy, much-branched annual with slender reddish-striped stems and needle-tipped leaves that form a rounded skeleton by fall. This non-native invasive dries, snaps off at the base, and tumbles across the landscape scattering tens of thousands of seeds, piling against fences and fueling fires.

Care · tuned to the Southwest

Water

Thrives on dry, disturbed ground with almost no water, germinating fast after any moisture and pulling deep soil water with a taproot; it exploits bare, cultivated, or overgrazed land.

Sun & exposure

Full sun on open, disturbed, unshaded terrain.

Soil

Invades disturbed soils, roadsides, farm fields, vacant lots, and railways, tolerating dry, sandy, and saline ground.

In the Southwest

Harmful because a single plant produces huge quantities of seed, the dried tumbleweeds pile up as fire fuel and road hazards, and it crowds crops and natives. Invasive — pull or hoe it out, don't tolerate it.

Common problems & fixes

  • Matures, breaks off, and tumbles for miles scattering seed and piling as fire fuel

    Fix — Pull or hoe plants when young and green, before they set seed and dry out; bag them rather than letting them tumble.

  • Rapidly colonizes disturbed ground and builds a large seed bank

    Fix — Establish competing vegetation on bare soil and cultivate or mow seedlings early; repeat, since seeds germinate over a wide window.

  • Dried spiny plants irritate skin and eyes and clog roadways

    Fix — Handle with gloves and long sleeves; for large infestations apply a pre-emergent or spot-spray young plants before they harden.

Pets & toxicity

Can accumulate oxalates and nitrates that may harm livestock if eaten in quantity; when dry the stiff spiny leaf tips are a mechanical skin, eye, and mouth irritant to pets and people.

Easy to confuse with

  • Kochia / burningbush (Bassia scoparia) — soft-leaved without sharp spine tips, turns red in fall
  • Native saltbush seedlings — Russian thistle's fleshy thread-like first leaves later become rigid and spine-tipped

Sources

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