The active ingredient in Aspirin is acetylsalicylic acid (ASA) in only tiny amounts, most of the tablet consists of starch and to my knowledge it is not sourced from willow nor has it ever been. Willow, like a lot of other plants, produces salicin (a plant hormone), that makes a lot more sense to me that using an aspirin (homeopathy for plants ?) as a plant tonic.
I'm interested to know what is willow water? Do you make it or buy it?