When something is wilting while there is no drought, then there is something wrong with the root. When I dig such a plant up, in most cases there is a larva of beetles that is enjoying to eat the roots.

i dont know about the crazy part.. but it just sounds like transplant shock/stress ...

and for whatever reason.. it only hit one plant ...

and if it is.. moving it again.. wont help ...

you are worrying too much ...

and it could be as simple as the increased shade.. is not allowing the soil to warm enough.. for it to get going well enough ... i bet its been pretty cold .. since you planted them ... and roots need warmth.. to grab hold.. and start working properly ... [which is opposite your sun theory]

i would just ignore it.. while insuring proper water.. which should be all that much this early ... if watered properly at planting.. i really dont know why.. in z5 .. they have needed repeated waters this early in spring.. heck .. it snowed here yesterday .. [unless you are further south z5's]

its all speculation.. you could be as right as i am ... who knows .. but i would leave it ... [see if you can feel a soil temp difference with your finger]

ken

I'm south zone five - actually with that new update to the zone chart, I'm moved to zone 6. Temps have been in the 60s-70s dropping to the forties overnight... though we are having a couple cold snaps last night & tonight, and i'm covering everything.

I probably am worrying too much though. Still it stinks, because I think this one is going to lose the main stalk from the wilting.

It sounds dry, could be a smaller root system than the others that caused the plant to experience transplant shock, or a tighter rootball (pot bound) where water isn't penetrating to the roots even though the ground around it may feel damp....Did they all get the same treatment when planting? Open up the rootball, watered in, not planted too deeply?

It's not wilting from too much shade.