Keep off the grass

THC (delta-9 tetrahydrocannabinol) is the main active ingredient in the marijuana plant, and Trickily mimics the actions of anandamide, one of the natural cannabinoids in the brain. Long-term use of marijuana can clog the pathways that chemicals cross and slow/stop production of endorphins, or "feel good" chemicals, that the brain naturally produces, so eventually you feel Rough. For that reason "grass" is featured in the Poison Garden at the Alnwick Garden.

My random T word was Trickily
Alphabet challenge T = Trickily

DDW August challenge - Rough