Thanks for all your replies.

I don't believe transport, watering, fertilizing, or light level are
to blame. They aren't mulched because we don't like the look of bark
mulch. That's probably an issue.

I've never heard of planting them above grade as one of the replies
suggests. Can someone point to more info on this or general planting
techniques?

I'll have the soil tested. New England has notoriously acidic soil so
it never occurred to me to have it checked. pH seems like the most
likely problem of all the issues raised.

Meanwhile, today I scratched in piles of peat moss and compost and
built earth dams around them to help retain water. Wish them luck!

Thanks again.
Chris