Tree Planting Fail

Tree Planting Fail

I live in the Piedmont of NC. I got three Yaupon Holly trees from an online mail order source in the first part of October. After they arrived I couldn't get them in the ground for about 4 days. I thought I did the right things planting them, dug a hole significantly bigger than the modest root ball (these guys are only about a foot tall) and used new bagged topsoil to fill it up. Watered every three days unless it rained (which it has been, quite a bit, but they are on the top of a slope so I expect drainage isn't much of an issue) for the first 2 weeks they were in the ground. Now their leaves have turned a nice red brown and have fallen off and I expect they are dead. Any suggestions as to what went wrong?
Wood Blewit Mushrooms

Wood Blewit Mushrooms

Pampass Grass

Pampass Grass

oops!

oops!

help with my kitchen!

help with my kitchen!

Plant ID’s Please

Plant ID’s Please

so my room is clean for once.

so my room is clean for once.