I wouldn't. Sounds like a fungal pathogen as you said(may be environmental causes too but I don't like taking risks) and if it were me I would never plant the same genus plant even as far as 3 feet away. I just wouldn't feel comfortable planting something with the thought that it can be affected with the same disease one day.

Thanks H!

Your comment concurs with other recommendations I've looked up.

Now the search begins for a suitable replacement shrub or small tree within a different genus.

Any ideas of what would work in that spot without fear of repercussions?

I mean I don't know how much space you can allow for that particular spot but I would search for trees and shrubs resistant to verticillium wilt. It could've been phytophthora root rot too but from what I know phytophthora usually only affects plants that are in less than ideal soil moisture conditions. I just wouldn't plant a taxus there though

Why not taxus? Aren't they gymnosperms and resistant to VW?

No extra room as it is vinyl edged circle about 4 ft. in diameter.

Because taxus are super susceptible to phytophthora root rot, if you’re peony did in fact get affected by that pathogen. Maybe a perennial best suits that area of that size but I can’t think of anything specific on top of my head but maybe look up what resists verticillium and phytophthora and also be hardy to zone 3?

I wouldn't either. I am not clear what pathogens are causing this - would be hesitant to jump in with verticilliums, botrytis, phytoptheras etc. without a better diagnosis but at the very least, I would replace existing soil to remove fungal traces. You could try the famous cardboard box method of replanting roses in the same spot (because of rose replant syndrome). Dig up the old plant during dormancy, clean off the roots so it is effectively a bare-root and replant in new loam (or topsoil from somewhere else in the garden) in a cardboard box with at least a cubic foot of space (12in x 12in x 12in ). This is a well known method in the UK. Obviously, care has to be taken to maintain the correct depth for a paeony and it will take a couple of seasons to recover blooming energy.

The peony roots were all dead and black. There was one small spot of a new shoot trying to grow so, not being interested in messing around with it, I dug them all and chucked them in the garbage.

I am not convinced it was verticillium or root rot either. I probably just moved it one too many times at the wrong time of year which weakened it and gave opportunity to whatever pathogen it was.

I might just plant some cheap perennials or flowers there for a while or maybe find a cheap, end of season shrub.

Thanks all.

;-)

Rereading my post to find I was talking rubbish (as per). What I meant to say was I would plant a NEW paeony in the same space as the old one, but with the added protection of a cardboard box (which will rot away but not before the new plant has begun to establish itself).

woodrose,

I got confirmation today from one of the owners of a large nursery in Brainerd MN.

He said moving weakens peonies and that makes them susceptible to fungal pathogens.

I got by with it once, but the second time did them in.

I asked if I should worry about planting anything new in the same spot and he said no.

I asked if there would be a danger of a pathogen lurking in the soil that would attack a new planting and he said no.

I won't be planting another peony now anyways just because I can improve things in that part of the yard by going to a woody shrub that's larger and blooms later with some color other than white (It's a zone thing). ;-)

Just thought I'd post this for others that might have the same questions.

Thanks again!