I don't know about Bletillas, but frost will destroy Cypripedium buds
and may harm the vegetation once they have broken dormancy. If they
are already growing, I would be tempted to grow them in pots this year
and plant them out next year. If you have squirrels in your area, you
might want to grow them in pots forever.

Given that most of my irises vanished, and some critter used the west end of
the flower bed as a latrine, it may well be an idea to keep them in pots.
But the crocus and lilies seem to not have disappeared. I'll have to think
about it, and perhaps run some tests with plants I don't particularly care
about. But I would like to see them propagate into sizable clumps, though I
have no idea how long that will take.

I doubt the biodegradable pots would last the year, so if I kept them in
pots for the year, should they be in plastic or clay? But then there is the
risk that being in pots, they may develop legs during the night and wander
off, if placed outside. There are, after all, more than a few ethically
challenged plant lovers out there.

What Cypripedium species do you have? Cyp parviflorum and Cyp.
candidum do well in a mix of peat and perlite, or just pure perlite.
Cyp. acaule seems to like a mix of peat and acidic sand.

The list of species just acquired is:
Blettila striata
B. striata var japonica alba
B. ochracea
Cypripedium gisela
C. reginae
C.calceolus var pubescens

Cheers,

Ted