If you plant one by one, neatly spaced apart, you won't have this type of nutrient cycling and moisture uptake.
Potatoes on a 2nd year old hugelkultur are amazing!
I live in zone 6b Connecticut
My parents have just added a few to their setup, but we're in winter here in Australia so yet to see their effectiveness through summer.
I do dig swales on contour and fill with wood chips to make garden paths. I harvest stone at that time to build garden walls and depending how deep the path is before filling I toss in some old logs before covering with woodchips for walking.
The end result is the walking paths become resavoirs for holding water and my feet stay dry and I'm left with topsoil to further raise up my garden beds and rocks to build with.
Basically rearranging the material that already exist on site to build a self renewing system!