Bright Red Berries Top Off A Devil’S Club Plant. Bright Red Berries Top Off A Devil’S Club Oplopanax Horridus Plant. Devil`s Club Stems Are One To Two Inches In Diameter And Thickly Covered With Yellow Spines That Are Ferocious. Tangling With A Spine Can Be A Painful Proposition Because They Are Very Delicate And Have A Tendency To Break Off Under The Skin.