no its shouldnt have been the cause. Did you tease the roots out too much? where there any grubs in the compost that you noticed? How long along ago did you plant it?

Oh heck Cafbat...I sympathise, I really do! Sometimes a plant will die despite the care and attention you give it, so don't despair...maybe the weather got to it, or it didn't get enough moisture? I'd dig it up and have a trip to the Garden centre and replace it if I were you :)

When you say you 'fed it bonemeal', what does that mean? Was the plant in a pot, and how much bonemeal and how often did you apply?

I have occasionally had the same problem with adding bonemeal to the planting hole and don't do it any more. I guess that it shouldn't actually touch the roots - maybe this is what happened to yours?