Ask Mr. Smarty Plants

Paeonia lactiflora (peonies) grow best in cool climates, because they will only bloom well if they experience a pronounced period of winter chilling. They require this dormancy so the plant can store energy to grow and bloom the following summer. A peony has to have about 400 hours of cold - not freezing - temperatures, about 40 degrees. Containers and north-side planting are tricks for warmer places. Peonies should be planted away from trees and large shrubs because they will have to compete for root space and nutrients, resulting in reduced size and quantity of flowers. Because they are native to Central and Eastern Asia, from eastern Tibet across northern China to eastern Siberia, they are not in the normal area of expertise of the Lady Bird Johnson Wildflower Center, where our goal is the protection and propagation of plants native to North America. However, here is The Garden Helper website on Peonies-Paeonia latiflora.

Offhand, we would say a south-facing bed in full sun in Tulsa, Oklahoma, already planted with liriope and red-tip Photinia, is probably not a good candidate for planting peonies. Red-tip Photinia is also a non-native of North America, a hybrid between Japanes and Chinese photinias. It has been bred to grow so fast that it often becomes infected with a destructive virus. See this Mississippi State University Extension Service discussion of "Red-tip Photinia almost eliminated." Liriope muscari is native to shady forest floors of Eastern Asia, including regions in China, Taiwan and Japan. With rhizomatous roots, it can be invasive and difficult to get rid of.

If you agree that your proposed spot is probably not the best place to plant peonies, may be suggest some native plants that occur naturally in Oklahoma that possibly would serve your purposes better? Since we are not really sure if you are looking for flowers or shrubs, we have selected Recommended Species for Oklahoma, herbs (flowering plants), perennial and 6 or more hours of sun a day. You can narrow your search and select for shrubs or grasses to go in the space between the tall Photinia and short Liriope. Here is a list of Native Plant Suppliers near Tulsa.