I read John Brady's The Going Rate set in Dublin. The expression wigs on the green was used several times so I had to google it to understand what it meant.
It’s an intriguing expression though it’s seriously out of fashion, just as are the wigs it mentions. Wigs on the green refers to a fight, brawl or fracas, or to a difference of opinion that could lead to fisticuffs.This was when men wore wigs and they would fall off in the fracas scattering on the grass.
I can’t leave an Irish expression without quoting a famous Irish writer:
But Tommy said he wanted the ball and Edy told him no that baby was playing with the ball and if he took it there’d be wigs on the green but Tommy said it was his ball and he wanted his ball and he pranced on the ground, if you please.
Ulysses, by James Joyce, 1922.