Just recently looked for these and found only one groundspawn and not this one. brought druid in to forage and found them around the 5th or 6th try, then stayed in that area to get the others i wanted.
I have found a couple ground spawns and waited patiently for a repop, however its seems they spawn in random locations and not the same spot over and over agian.
ground spawn is all over the place. seems to be mostly on the perimeter, although i swear the spawns have been severely cut back recently. maybe it's just me.
anyway, try looking between the perimeter wall and where the ground starts to crack. i've found all of mine in between, if that helps.
Ground spawn in various places in The Devastation..usually followed by picking up a psilocybe of rage then the pitaya appears next, not always, but usually..all I can say for now..just stay invized and wander..