Yes, I know the recommendation is against spring transplant. But it is so much easier in the spring to figure out what you're doing in a transplant.

I moved half of a very old cluster of Peony to a slightly sunnier location, and from a level bed right next to a giant pine tree to a raised bed next to a different giant pine tree.

Since I never dug up a Peony before, I had little clue what to expect. I broke off more than I took of the half I moved and I think I broke off even more of the half I didn't take.

I was surprised at how big the tubers and tuberous roots are, and more surprised at how fragile it all is, with the single annoying exception of last year's stems. Those stems are super strong and super attached to the main underground structure of the plant ("crown", or "tuber" or whatever). I'm used to other perenials where I just break off last year's stems by hand, rather than having clippers with me. I did quite a bit of harm trying that, before going back for clippers.

As much as I could, I avoided even touching the red shoots. Some broke off anyway.

I was surprised that half the tuberous roots go down just a few inches before turning horizontal and going off to the far distance (but over many years there, never sending up new shoots in the distant spots reached by those roots). It looks like the ones that stayed vertical went similarly far down. But all the vertical ones broke (with almost no force) when I disturbed the plant. Almost all the horizontal ones similarly broke. All that happened to the half I was trying to lift, but also to the half I wasn't trying to lift.

I was also surprised and unhappy at how few ordinary roots came with the tubers. I think they are so fragile the weight of the dirt ripped them off (as it became looser and freer to move), even though I was careful to lift from below that dirt.

Other than the red shoots, I'm not convinced everything being so fragile is a result of wrong time of year. Please correct me if I'm wrong about that. Are the tuberous roots tougher at other times of year?

I did not intentionally separate anything. The break into 5 sections (3 of which are in the photos below) happened in the first exploratory lift of dirt deep under the half I wanted to take.


Next is a closeup of the above:



Next is a closeup of the above:


The right end of this next one certainly looked like a new shoot developing from the narrow (far) end of a horizontal tuberous root. It happened that horizontal root started from the north edge of the cluster and pointed back across to the east edge of the cluster. No shoots ever came up outside the cluster, which has been the same place and size for over 30 years. So do those horizontals normally extend the cluster and something else is wrong with the original location? Or was I misunderstanding the appearance that this shoot is from the far end of a horizontal?

Really big, old clumps of peonies are always going to be a challenge to move. Some varieties make an enormous amount of roots—had one in my back garden with a single root over 4' long and it'd only been in place for around 5 years! No, I don't think the feeder roots are any more resilient in the fall but they don't need those little hair-like roots as much then and they have a better chance of growing new ones before the next growing season if they're disturbed in the fall. I've dug up a massive amount of peonies over the last few years and I think it's almost impossible to get a large one out of the ground in one piece.

As for your little shoot in the last pic it's hard to say, you'd have to remove all of the dirt and look at it more closely. I assume your peony is a lactiflora. They typically don't have adventitious roots meaning they don't usually form eyes on parts of the root further away from the crown and left over bits of roots once divided don't normally grow eyes, although I've been told it can happen. If your peony is a herbaceous hybrid it could be adventitious because of a non-lactiflora parent, those can and do grow eyes away from the crown and, when divided, pieces of broken off root can grow eyes and start new plants. Seems most of the coral herbaceous peonies share that trait. Your little shoot could also be a seedling that started really close to the parent but impossible to tell with the soil on it.

I could see more when holding it than I could show with a photo. It was at the far tip of a tuberous root and it was physically attached, not just sharing dirt.
Some plants fuse roots with siblings, when crossing roots get thicker into each other. It is hard to tell for sure, but many spots in this underground monster appeared to be tuberous roots fused through each other.
So if that wasn't a shoot from that tip, my next guess would be a seedling whose roots immediately grew through (definitely not just around) the tip of the thick root.

Now that I did it wrong, I expect the next step is to water a lot to compensate for the shortage of small roots. The part I just put into the raised bed has very porous soil under it and a little dry 10-10-10 mixed in as I planted. So it should be impossible to drown the roots with over watering and not too likely to wash too many nutrients out with over watering.
I would think all that stored energy would be serving some purpose. So it should be able to grow new roots with little input other than water.

I am less clear on how much to water the part I broke and left behind. That isn't in the badly drained soil of much of my yard, but it isn't in super well drained soil. So over watering would be harmful.

I think I'm most curious about how/why the plant built up such a massive store of whatever is in those tuberous roots. Each year I have been getting two or three flowering stems with one to three flowers each, plus three or four non flowering stems. There were a lot more of those red things than I ever get stems, so something must be happening to most each year before they turn green. Meanwhile, the plant is clearly not using that massive store of whatever, but just continued to build it. The underground mass was absurdly large compared to anything that was ever above ground.

I was wondering/hoping whether it is herbaceous. I left a LOT of big long horizontal tuberous roots in the ground after accidentally breaking the thickest part of each near the crown. So if those are herbaceous, I might have some new shoots sometime this season, and new plants next year. It is just so incredibly much stored something, it is hard to believe it does nothing.

Hi Jsf, I agree with Liz's comments.

Good luck with your adventure. You will need to be careful about overwatering through the summer, as those little white roots die quickly when they are exposed to air for more than 15 minutes. Peonies are not inclined to grow those roots in warm weather. Should any of the above ground foliage start showing signs of rot ( like blackened stems) cut them off and dispose in the trash.

Most of us have dug up a peony in the spring because of a necessity, and they have survived. .


Good luck! And keep us updated.

Overwatering can cause a lot of problems as well, Jsf. The thing that helps IMO with spring transplants is to give them a couple of hours of morning sun, early, then shade for the rest of the day for the first week or so, move the shade away slowly after that. Keeps the stems from needing quite as much water—and it does not matter one tiny bit how often you put it out there, they can't draw it up without the little capillary roots. Slowing the need for water lessens the stress quite a bit on spring planting.

I think we have had enough clouds, I don't need to artificially shade.

Initial appearance, the ones I moved are doing well. The ones I think I broke (but didn't get a good look at and didn't move) are doing badly. Those get less sun. When I first lifted slightly from deep under the half I wanted to take, the other half shifted a little and became very loose. So I think the crown is sitting there broken off from all the tuberous roots. There was absurdly little force or distance involved in breaking that. So it must have had zero flexibility and zero strength. But as far as I can tell from the pieces I lifted out, the tiny roots are mainly from the crown (not from the tuberous roots). So the half I didn't lift should be in better shape on tiny roots.

All shoots are still red. I don't remember when they normally turn from red to green.

Up to yesterday, the chunk I left behind was doing well and the chunk I transplanted even better.
Each had several cherry size flower buds.
Suddenly all the flower buds on the transplanted one shrunk to tiny and turned black, and all but one bud on the untransplanted.

Any idea what went wrong?
What can I do better to get them to flower next year?

I believe it is lack of resources for plants. Peonies are heavy consumers and need a very developed root system to open fully double flowers (I suppose your peonies are doubles). Especially peonies you re-planted lack more nutrients and water because you inevitably destroyed some root when dug them out. No worries, next year they will probably bloom nicely!