I was caught out last year with the delivery of a large collection of perennials and some bare root roses - which arrived 2 days before Xmas. Great. And I had to queue at the post office for the darn things as well.
I did manage to keep them going with a few smaller plants lost. But this year I decided to avoid the worry and simply wont order any plants til spring. The perennials offer was repeated in the spring, was cheaper and of course, the ideal time of year to plant for success.