The grid type supports sold for the purpose are not perfect for every peony but they help. As the peony grows the grids disappear in the foliage, so they are hardly noticeable. To have the large double blooms laying on the ground when in bloom is not attractive. Al

However since it normally rains when the large doubles bloom they end up looking ratty. I find that on these it is better to cut and bring in before it rains. The use of supports is a matter of individual taste and type of peonies that you have. Some need support others have their flowers way above the foliage because they were originally ment to be cut for arrangements in the house. I agree with calistoga that the grids are best for peonies if you need them. The loops around the plant sometimes will cause the stems to break over them in high winds.

People use all kinds of things to hold their plants upright but after the plants have bloomed if the foliage is too compacted remove the supports so that air can circulate among the stems.