Does anyone know when exactly tree peonies start growing their feeder roots?
I have got lavender Hill on its own roots and some cheap tree peonies from the grocery store and kept them in the pots till the fall. I remember that I was surprised by how many feeder roots they had that fall. However, I don't remember when I planted them, but I would like to know when exactly they started growing their feeder roots. In September, October, or perhaps in November? I assume the temperature must drop to a certain point, or maybe not? Does anyone know? Please enlighten me

Hi Jasmin - As I have been digging so many peonies lately, tree and herbaceous, I can reliably say that those that are still growing/have good green leaves still have many small white feeder roots while those whose foliage has pretty much shut down for the winter no longer have visible white feeder roots. I would say this points to a MUCH earlier initiation of feeder roots than you suspect and a decline as the temperatures decrease. Logic has it that when they have finished blooming they will start to 'reload' for next year's blooms.

Interesting When I planted the baby tree peony on its own roots, which I got form the neighbour, the peony was dormant. It lost all leaves, but there was one leaf bud, which looked alive. However, the main root looked good, much bigger than the part above the ground. It also had a little feeder root, which confused me. The peony was dormant, but the feeder root was still there.

Now, I don't quite understand why we have to plant tree peonies in the fall They will not start growing new feeder roots until next spring. They cannot get nutrition until spring. What can they absorb from the main roots? Water only? I don't understand the cycle Please enlighten me.

I asked Siri because I was thinking it was because they need cooler weather to grow a good root system in order to flower and needed the cold temps to set bud.
But this is what Siri said… Fall-planted peonies tend to establish themselves more quickly than those planted in the spring, and they will flower sooner. Spring-planted peonies seem to run about a year behind fall-planted peonies in terms of maturity, growth and flowering.

In my experience, I remember having a few very stubborn tree peony's that took 3 years and (a good threatening to bloom or they were out) …before they finally bloomed .
I have tree peony's 25 years old. I wonder how old that is in plant years?

Jasmin - remember that the big 'carrot' of a root is their food storage organ and this is what they draw on come Spring. So-called feeder roots develop, when the ground warms up, in order to replenish and fatten the large roots which on their own cannot do this.
Fall planted peonies have at least 6 months to acclimate before they need to start growing again whereas Spring planted ones have to go bare root straight from a warehouse maybe, to a garden and start growing almost immediately