Recently, I rescued 2 peony plants that had been growing in a nearby lot for years. The house was being renovated and paint had been splashed on them. A worker was about to tear them out and throw them away, but I persuaded him to dig them up and replant them. I managed to get some of the paint off but not all. There are a few leaves left on each plant and the stems are still green and healthy looking. I put some compost in the planting hole and a little more around the plants because the soil is quiet clay-like. I’ve been watering them and they seem to be staying alive, but should I be adding some fertilizer or something else to the soil? I’m worried that because there’s still paint on some of the leaves, the plant will die!
It sounds like you have done everything right! At this time of year, peonies are getting ready to lose their leaves in any case; in fact, in a few weeks, you can tidy up the plants by cutting the stems down to a couple of inches above the ground.
The compost will be dragged down into the soil by earthworms, helping to improve it. Keep the soil moist but not soaking wet, until freeze up.
Just before then, you can add a a 2 inch thick layer of composted manure around the plants to provide additional nourishment.
Because the newly planted peonies roots are just below the soil surface, there is a risk of them heaving out of the soil during freeze-thaw cycles in the winter. You can add a thick layer of mulch on top of the plants to help prevent this; just remember to pull that mulch off gently in the spring. Next year the roots will establish firmly and you won’t need to mulch on top again.
However, peonies are heavy feeders, so adding the compost or manure each year is a good idea.
Good for you to rescue the plants: peonies are very hardy and can live for as many as 50 years.