Just do a search for peonies for the south and you will find all kinds of suggestions. The chill hours mentioned in many sites are the number of hours below 40F.

Auburn University has been doing a study of peonies for the south. They received a number of plants, many tree peonies, when Gold Port went out of the peony business and moved to the North West. So they are another source of information. They have also sent plants all around the area to parks and gardens so you might want to contact them for places you can view peonies, both regular and tree.

Rather than tell us your zone, which is mearly your lowest average temperature, where is the location of your garden. A general location may be all that is needed because Peony Man was from Louisiana and knows the areas there.

My property is 30 miles northeast of Baton Rouge, Louisiana...hill country with clay/loam soil.

Yes you can grow peonies that will flower in your zone. You will need to plant them so high that the top of the roots containing the buds are not covered with ANYTHING through the winter. The buds must be exposed to AIR temperature. I have many varieties of herbaceous peonies here and have not noticed a difference in their ability to accept your warmer winter temperature. They love clay/loam soil and would only suggest working finished compost into your soil to a depth of about 2 feet before planting. With your high humidity summer climate I would be sure to space your plants far apart to improve the air circulation and help avoid moldy foliage. Al

Can I grow peonies in Houston . It is hot and humid climate.