Repotting Paeonia

[JPB]

I've repotted some of my (herbacious) Paeonia's into larger pots. To make the stress to the roots as minimal as possible, I did it while the pots were frozen outside. Most species I grow do not mind having their pots completely frozen for a short time.

So far, it seems a good method, see my pictures, they speak for themselves:

[Ezeiza]

Hans, which is in your experience the minimum pot size for flowering plants (of species, I assume hybrids are too large to be grown in pots, right?).

[Lesley Cox]

Will the now frozen roots find their way happily into the new compost? Some plants (notably rhododendrons, which are very different of course,) need to have their roots teased out and introduced carefully into the new compost or they tend to continue round and round in the same space as if they were still pot bound.

[JPB]

Alberto, I can not say what the minimal pot size is. So far only one flowered in a 25 cm pot. Another in a 16 cm pot has a flower bud. Deep pots are benificial but not necessary.

Lesley, I have not observed that yet, but as Paeonies like rooting space so I expect that they will grow into the new soil no problem.

Hans

[Ezeiza]

Thanks, Hans.

The photo sequence is superb.

[johnw]

Very clever Hans. They are always so hardy to transplant.  I will try your method on our tuberous begonias. 

Seriously now, can you recommend a general mix for Paeonias?  We have many problems with potted P. suffruiticosa v. spontanea, especailly early-summer collapse; I suspect the mix as they are never firmly rooted.

johnw

[JPB]

Thanks Alberto, a picture paints a thousand words....

John, I don't have a good mix yet. I sieved the best commercial potting soil in the Netherlands (which is mediocre at best ) and added vermiculite and Seramis for better draining. Still the trick is to keep the plants out of the winter rains and freeze-thaw alternations. Keeping them outside the previous winters has resulted in loss of many of my mascula's and peregrina's. P. officinalis survived better, still some plants died.

This winter I kept them much drier and covered outside, or under the bench in the frost-free greenhouse. Frost is not a problem, but I don't let them frozen for long time or at heavy frost. All plants are healthy now and have nice leave buds, some might flower, I hope.

Any suggestions for a better potting mix are welcome. The best fertilizing regime is not yet clear to me either. Low nitrogen seems to be beneficial. A professional grower advised me to keep feeding well into autumn as the roots take up nutrients after the leaves have died down, but I'm not sure if that is a good advise

Hans