This is one of the things that I disagree with peonyman about even though he is better than I am at grafting. If you still have the stems try two or more things with them. If you have access to peony roots that could be used for grafting try it. Just because something does not work for one person it might for another if the conditions are right. Remember to graft the old wood to the new root. Second as an experiment get some of the crystals that are sold for water retention that expand when water is added to them. Wally world has them as do florists, your neighborhood nursery might also. Get two or three containers, I would use glass jars. Put the crystals in the containers to one add just water, the second add water plus aspirin or pieces of willow twigs, and to the third add water and use a small(less than 1/4 teaspoon) amount of fertilizer. Add the stems after cutting off the leaves and new stems. Put the jars in a dark warm area and see what happens. My thought is that if the containers are kept in a dark warm area for about two months and then brought out to the light roots should form along the stems. Since I heard of this experiment on other hard to root plants I have been wanting to try it. However with my deer and rabbits I have no stems this spring to try anything using old wood. I would like to report that many of the tps that were eaten are sending up really healthy new stems.

That would make things a lot more troublesome if seeds from a TP turn out to be a random color, but the good part is there's a chance for more varieties with the seedlings I've been producing. BTW I have a potentially much easier method to duplicating a specific TP. Why don't you just build a mini-raised bed over the entire TP so that a majority of the plant is under the soil, then create cuts and rub rooting hormones all over the branches, and fill in the raised bed box with loose soil afterwards? If TPs root as easily as blueberry plants, the box should get filled up with roots within a season, and by fall once the plant goes dormant, it can be time to cut up the entire plant based on where the rooting occured. I'm not sure if it works well with TP, but if I wanted to make more of a certain kind of flower, this might be the method of choice.

Thanks a lot for your advice. I am gonna research both the gritty mix and the 5-1-1. Since I need to re-pot because my soil is wrong, do you suggest that I shake or remove much of the old soil from the roots when I replant? When I was videos on re-potting, they seem to transfer much of the soil but I'm concerned that it will also carry the problem to the new pot. I wasn't able to find the 5-1-1 online. Do you have a suggestion on where to get this?

bpeterson, that root is still several years away from flowering, sorry. If you live in a fairly warm zone a peony might make it through the winter in a pot, think the warmest I've seen people post about potted peonies has been zone 6. If you want to try it I'd replant and just leave it alone, pulling it out of the soil breaks off the little hairlike roots and sets it back further. Like Nancy said peonies are pretty hard to grow in pots, I'd experiment with your root by replanting it in a large pot just so it doesn't have to be moved if it survives since it'll get quite large. If it comes back and increases you might want to double pot it to insulate the roots from summer heat. By this I mean plant it in one of the black nursery pots then put that pot inside a bigger ceramic or similar pot big enough so the sides don't touch. You can put moss or some biodegradable mulch over the soil if you don't want to see the ugly pot but keep it away from the stems--mulch that stays wet could cause rot damage to it. Make sure to water only when it's dry at least down an inch or so--too much water is just as dangerous as too little so make sure your pot(s) drain well. Peonies want full sun but the roots will get overheated quickly in a pot, if you can shade the pot somehow while allowing the growth to get sun that would be your best bet. If you can keep this one alive and it prospers I'd think I'd reward myself by purchasing a 2nd one from a nursery that already has buds so you can have blooms next spring. If you wait for the one you have to bloom I think it'd be at least 3-4 years, sorry.