Given the way they’re describing it, US south/southeast. The pitcher plants that grow there grow in marshes and swampy grasslands are from there. Pitcher plants elsewhere in the world are a different type all together, and are generally epiphytes or close to it.

Except Australia and certain south American highlands. Or the pacific northest US. There are like 4 families of pitcher plants, only two of which are closely related (counting sarracenia and darlingtonia together with heliamphora in the family and nepenthes and cephalotus on their own).