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Salsola tragus

prickly Russian thistle

Overview

Salsola tragus, prickly Russian thistle or tumbleweed, is a bushy summer annual in the amaranth family, forming a rounded plant 1-3 feet (30-90 cm) tall and wide. Young plants have soft, thread-like leaves, but as they mature the leaves become short, stiff, and spine-tipped, and the stems often show red or purple stripes. Small, inconspicuous greenish flowers form in the leaf axils in summer and fall, each backed by papery, sometimes pink-tinged bracts. After the plant dies and dries, the stem snaps off at the base, and the whole skeleton tumbles in the wind, scattering tens of thousands of seeds as it rolls. Native to the steppes of Eurasia, it has naturalized across the western United States and other dry regions, where it colonizes farmland, roadsides, and disturbed ground and is listed as a noxious weed in several states. It tolerates drought, heat, and saline soils but needs open, bare ground to establish. S. tragus has no garden use and is managed as an agricultural and rangeland weed.

Native Range

Salsola tragus is native to the dry steppes and deserts of Eurasia, from eastern Europe across central Asia. It has naturalized throughout the western and central United States and other arid and semi-arid regions worldwide. It grows on disturbed, open ground such as fields, roadsides, and overgrazed range.

Suggested Uses

Salsola tragus has no horticultural use and is treated as an invasive agricultural and rangeland weed. Young plants are occasionally grazed by livestock before the foliage turns spiny. Land managers focus on controlling it to protect crops, range, and roadways.

How to Identify

Recognize prickly Russian thistle by its rounded, much-branched form and short, stiff, sharp-tipped leaves on striped stems. Young seedlings have soft, fleshy, needle-like leaves before the spiny mature foliage develops. Tiny greenish flowers sit in the leaf axils, each with papery bracts. The plant breaking off at the base to tumble as a dry skeleton is its most familiar trait.

Appearance

Size & Dimensions

Height1' - 3'

Width/Spread1' - 3'

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~12 weeks

Summer Fall

Flowering occurs from midsummer into fall, roughly July through October. The small greenish flowers are wind-pollinated and easy to overlook. Seeds ripen as the plant dries, then disperse when the dead plant tumbles.

Detailed Descriptions

Flower Description

Greenish with pink-tinged bracts

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 - 8.5(Alkaline)

357912

Soil Types

sand loam clay rocky

Drainagewell drained

Water & Climate

Water Needs

Very Low

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Prickly Russian thistle is an unwanted weed rather than a cultivated plant, growing in full sun on dry, open, disturbed soils, including saline and sandy ground. It germinates quickly on bare soil, grows through summer, and matures as it dries in fall. The plant is drought- and salt-tolerant and sets seed even under harsh conditions. Control relies on removing or tilling young plants before they set seed and on keeping ground covered, since seedlings need open soil. It has few natural pests in its introduced range, which contributes to its spread.

Pruning

Cutting, tilling, or pulling young plants before seed forms is the main control method. Mature plants are removed before they dry and break free to tumble. Cut material with ripe seed is bagged or burned rather than left on site.