Hi all, about 4 years ago I bought a tree peony 'Koukamon' for my daughter's garden in Salt Lake City. She loves the dark red flowers, but last year we had one 'sport' pop up from the base with an unattractive mauve/pink color flower, and now she says this year there are several of these sprouts.

Could anyone advise us what to do about this? The one last year, we just cut off right down at the base of the stalk. I hoped that would discourage the sports, but it seems not.

Do these plants revert? Would this be a sprout of the root stock it is grafted on? Is it planted too shallow?

Most likely these are coming from the herbaceous nurse root that tree peony was grafted onto. How deep did she plant the tree peony? One should plant that nurse root a good 8 to 10 inches deep so that the tree peony will begin to make it's own roots and the nurse root will die off. Keep cutting off the volunteers from the nurse root and this fall I'd probably dig the tree peony and plant it much deeper.

Alana, what do you think????

Thanks! They may be moving by this fall, so we have an excuse to take the tree peony along when they go. (I'll find something else to put in its place)

You can also just yank out the herbacious stock when it comes up. It can weaken a tree peony plant by giving energy to the herbacious stock, rather than just giving energy to the tree peony.

They say that on an older enough tree peony, it has grown enough of its own roots to actually cut the herbacious root stock off of it by digging the whole plant up. The roots are much different and are very easy to discern. That said, I haven't done it myself. I've just listened to wise growers tell me how to do it.

I find yanking the herbaceous growth out as it comes out to work just fine. The tree peony I speak of is planted plenty deep, I have just been told that the root stock is adventitious and doesn't even need eyes to grow! Most US growers don't use this type of root stock.

Thanks, I'll tell her to give that a try.