Toadflax

“What on earth did you put in that stuff?” “Bug-bane, barren-wort, penny-cress and blood-root, catchfly, toad-flax, nap-weed and wormwood,” said Catweazle.

One morning she had me traipsing out at the crack of dawn for prickly poppy, toadflax, spiderwort, and skeleton weed. If that doesn't sound like the makings of a witch's brew, then I'm the queen of England.