Green’s Dictionary of Slang

push up (the) daisies v.

also kick the daisies, pick..., shove up..., push up the poppies
[prob. based on undated gravestone inscription: ‘With the tips of his toes / And the end of his nose / Turned up to the roots of the daisies’ variously attrib to an Irish or Scottish graveyard]
[1910s+]

1. to die; thus pushing (up the) daisies, dead.

2. in fig. use, to waste time, to lead a pointless existence.