Well, I can't tell you about the arid climate part. Maypop is fully hardy here under deep (6" or more) winter mulch. I've been growing it since the early 1990s, albeit with a break of a couple years when I lost mine to (surprise, surprise) voles. I've never had a ripe fruit, although once or twice came sort of close, beginning to color the arils and getting decent aroma, with the shell also beginning to turn slightly yellow.

I think they just need more heat than my climate provides. I guess in NM it might work, depending upon altitude, etc.

Don't pay big $$$ for a small start. They are really easy to germinate from seed, about like starting a morning glory or a sunflower. I have bought seed in the past from Sand Mountain Herbs in Alabama and from Johnny's.

Here is a link that might be useful: Maypop seeds at Sand Mountain

Thanks so much for the response. That's good to hear about the success of a thick mulch, and that the seeds germinate readily.

I don't know what the difference in Growing Degree Days is between here and where you are, but I'm optimistic about them being able to ripen. Even though cool nights here around 7,000 feet slow things down some summers, I'm still able to grow and ripen chiles, tomatoes, melons, watermelons, okra, cotton, without any trouble.