from wiki:
In the Americas, the monarch ranges from southern Canada through northern South America.[4] It has also been found in Bermuda, Cook Islands,[34] Hawaii,[35][36] Cuba,[37] and other Caribbean islands[10]
p18) the Solomons, New Caledonia, New Zealand,[38] Papua New Guinea,[39] Australia, the Azores, the Canary Islands, Madeira, Gibraltar,[40] the Philippines, and North Africa.[41] It appears in the UK in some years as an accidental migrant.[42]
I don't think I'll be investing in one of Subrosa's water snowball plants - anywhere less like a swamp/wetland is hard to imagine in my location!
My Monarchs are partial to the nectar of Rosemary (horizontalis, not ordinary!) and of bottlebrush.