sleep flower

noun2

1. •
   Any flower whose consumption, in whole or in part, causes the consumer to fall asleep.

   • […] The wind will shift and the way will open. […] Then, go back to the garden with the sleep flowers. Use Jinn's power to control the wind, and spread the sleep pollen into Rolante castle. — 1995
2. •
   (literary) A poppy, particularly the opium poppy, Papaver somniferum, whose extract was traditionally used as a sleep aid.

   • The sleep-flower sways in the wheat its head, Heavy with dreams, as that with bread: The goodly grain and the sun-flush'd sleeper The reaper reaps, and Time the reaper. — 1908