First the dire warning that this is a bad time
of year to dig and move peonies. if you can delay this until August or
September you'll have better results. And not knowing where you live makes
the answer a bit harder, too.
BUT if they must move and you get free plants,
First , make sure the plants you get (or
help dig) are divided into small enough divisions. Big divisions will not
do better than a division with 3 to 5 stems. That is enough and they'll
recover and grow new roots faster.
Keep them out of the ground for a minimum amount
of time. This may mean digging holes ahead of time, mix in some compost
and slow release fertilizer, a handful of bone meal etc. Keep the freshly
dug plants damp and out of the sun. Plant in full sun and make sure they
are replanted at the same depth they were growing and be especially careful
not to plant too deeply. If they are too shallow
you can always throw some more dirt on them,
but too deep is harder to alter. After planting, water them well
and make sure they are in a well drained site. Then I'd suggest a regular
watering twice a week to keep them from drooping, but don't be surprised
if they go dormant early. Fertilize again in August/Sept.
Don't expect bloom next year and hope they'll
recover fully in 3 years.
Check out Peonies by Allan Rogers,
Timber Press for more info.