They'll be fine Mary - worry ye not
They can, apparently, get enormous when the seasons allow. Indeed some suggest allowing a 3' diameter for them because, in a very good year, they may get that big. I plant them closer than that because, whilst in may reduce my "per plant" yield, in most years it improves my "per square foot" yield. That will limit my plants I think to not much bigger than about 2' maybe 2'6" high. Given yours can spread without bumping into another plant they may get bigger, but it won't hurt them!
If they block out the light, I'll send prince charming around to cut his way in
Mine flower every year - doesn't seem to affect the tubers