misplaced summer Day in May for Ray (edit)

[just mercedes]

an early shower
obliges an earthworm to rise
a lilac to burst.

early showers
lure earthworms
lilacs burst

early showers
tempt earthworms
lilacs burst

No, sorry, I think the 'obliges' wrecks your 'ku. Maybe try it another way around:

lilacs burst
earthworms rise ~
an early shower



because a 'ku is a snapshot of time, I think 'showers' should be singular - only one can happen at a time