This brought to mind something I read a few weeks ago about watering a
sickly orchid plant with a small pinch of aspirin in the water.
Apparently it is supposed to get rid of some orchid virus or other.
Aspirin is of course salicylic acid, from willow trees.

In Gerald Durrell's 'My Family and other Animals' his tutor's mother
used to put aspirin in with cut roses to make them last longer.