Yellow Star Thistle* Centaurea solstitialis

This relatively new arrival in the area is found in dry fields, along roads and trails, and other disturbed areas. An annual, with bright yellow disk flowers, that blooms May - October. Spikes ¼ to ¾ " long grow below the flowers and are painful when encountered. Horses that feed on this plant develop an incurable and fatal brain disease.

Plant size: 1-2 ½' h

Tocalote - Maltese Star Thistle+ Centaurea melitensis

A smaller cousin to Yellow Star Thistle, this common annual is found in dry fields, disturbed areas, and along trails and roads. An annual, with disk flowers (some are yellow), that blooms May - June. Branched spines, up to 3/8" long, are purple or brown tinged.

Plant size: 1-2 ½' h

Black Mustard* Brassica nigra

Extremely common annual found growing in meadows, disturbed areas, and along trails and roads. Bright yellow petals grow on top of erect branching stems, blooming February - July.

Plant size: 2-8' h

Tree-of-Heaven*Ailanthus alitssima

A native of China, this deciduous tree grows rapidly, self-seeding and producing new plants with suckers. Leaves grow from 1 - 3 feet long. Does very well under adverse conditions.

Plant size: 50' h x 50' w

Photo Credit:
*Br. Alfred Brousseau, Saint Mary's College
+Charles Webber, California Academy of Sciences

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