Early fall (ie late Sept to November) is the best time for planting or transplanting most things in the temperate zone.
There's less heat to stress the plants, there's more rain, and plants have just enough time to send out new roots so they will be established by Springtime (and also because all plants begin growing - underground - well before what we consider Spring planting season. Thus fall planting gives them a double head-start to prepare. Plants grow roots at least a month before they show any green).
I planted three Knock-Out Roses this weekend. They are the easiest, most care-free, toughest shrub roses around. That's why they have become the biggest sellers. (Bill Radler built them - not the government - and he is getting rich from his creation. It's called genetic engineering.)
September to early October is the time to plant Peonies, too. I remember when everybody's grandma had a circular peony patch somewhere, but now people just put them in borders. Prepare their soil well, because Peony plants last a long time and take a year or two to become established and strong.
People recommend full sun for them, but half-day sun seems fine.
Here's How to plant and grow peonies.
Image is from White Flower Farm's Peony page.