HEADCANNON:

After I created the map of PopTopia, a place of original PopCap characters, however, you thought Suburbia(from PvZ) is part of it but it's not.

According to PvZ guide book, comics and few trivias, that Neighborville/Suburbia takes place in US of America.
Not just that, also Tiki Island from Zuma's Revenge takes place in part of Polynesia Islands.

Sorry for inconvenience, guys.

See the fictional chronology and trivias here(it's still work in progress):
popcap-fanfiction.wikia.com/wi…