Staggerweed or stagger weed, a plant so named because it produces staggers in livestock that graze it, usually refers to Stachys arvensis.
It can also refer to other plants including: Consolida regalis syn. Delphinium consolida Corydalis cava Delphinium spp. Delphinium tricorne Dicentra eximia syn. Fumaria eximia Dicentra canadensis Dicentra cucullaria Helenium autumnale Jacobaea vulgaris syn. Senecio jacobaea, also called staggerwort