Oh sorry just found out its a Macleaya, plume poppy comes from china but grew accidentally, but is a stunning species for my large garden

I'd also go either autumn or spring. its a statuesque plant. that's one 'good' accident.

I never get accidents like that...

I've always got something new growing in the garden, I think its because we are in the country I gets visits from foxes, hedgehogs, wild birds, and even a resident grass snake lives by the pond. This will be why I get strange things growing. All this wildlife brings it in