Here is something to consider: you could always grow sweet potato no matter how short your (remaining) growing season if you were only interested in harvesting the leaves. Most of us in North America don't give any thought to sweet potato leaves as a crop, but they are highly nutritious and very popular in other parts of the world. I've eaten them, and they're great! A go-to hot weather green crop, and very productive. You can harvest heavily if not intending to dig the
roots. Or if a
root crop is in your future, don't harvest from any one plant's vines quite so heavily and you can get too harvests from one plant over the
course of a year, though likely the root crop will be somewhat diminished.
I cook them just like spinach. Very mild tasting.