Plants of the San Marcos Foothills Preserve

Ambrosia psilostachya (Western Ragweed)

Fairly common native perennial herb found in disturbed areas, especially near creeks and at the restoration sites. Flowers are yellow and inconspicuous. Blooms summer through autumn.

Ambrosia Psilostachya

Ambrosia psilostachya (Western Ragweed). NATIVE. Sprout pictured in late winter.

Ambrosia psilostachya (Western Ragweed). NATIVE. Sprout pictured in autumn.

Ambrosia psilostachya (Western Ragweed). NATIVE. Sprout pictured in autumn.

Ambrosia psilostachya (Western Ragweed). NATIVE. Sprout pictured in late winter.

Ambrosia psilostachya (Western Ragweed). NATIVE. Sprout pictured in late winter.