Green’s Dictionary of Slang

April showers n.

flowers.

1960		J. Franklyn Dict. of Rhy. Sl. 33/2: April showers Flowers. 20C.
1971		J. Jones Rhy. Cockney Sl.
1992		R. Puxley Cockney Rabbit.
1999		R. Walton ‘Cockney Jack’ 🌐 That take a fright, when Jack came home from work, he kissed his struggle and strife and handed her a bouquet of April showers.