Hi John and welcome to GoY. Are you asking about a herbaceous Peony or a Tree Peony? If it is a herbaceous one then you won't find better a dice than that offered by the RHS copy and paste the URL below.

https://www.rhs.org.uk/advice/profile?pid=671

In short yes this is a good time to replant, though you could wait another month where you live. Can be grown in a container if it is large enough and has drainage holes in the bottom, don't select anything that is narrower at the top than part way down or you'll have to break the container when it comes time to repot. Most Peonies prefer neutral to slightly alkaline soil.

Dear M G many thanks for your advice .....
As our soil is very sandy and full of clay would it be OK to replant/pot using SOME GOODWINS MULTIPURPOSE COMPOST.....

Also a friend has just given us a clump of agapanthus bulbs (3) of them - Would you separate the bulbs and put them in the same compost in the ground or in pots ?

Dear MG - you've guessed by now we know nothing about gardening - by the way the peony is herbacious

Better to use an ericaceous compost to be honest... Suggest you ask the agapanthus question separately as I'm the only one who will see