Maybe the owners of this house were inspired by these?
It was really hard to photograph as I there is no footpath on the opposite side of the road and this house sits higher than the road. Driving past this place really jumps out at you as the houses on either side are so “normal”.
On closer inspection it looks like there is a lemon tree in the front garden and a grape vine closer to the house. I wonder if that was Wisteria at some stage and therefore inspired the colour scheme?