I can grow it, but can I say it?
It looks to me like it would be said "stew-pice" (the pice rhyming with nice). "Stoop-ice" also seems reasonable. But both sound too much like "stupid" to some folks. My family laughs when I talk of stew-pice tomatoes, but they won't be laughing when we have early tomatoes from the garden.
So how do YOU think Stupice should be pronounced?