Container-grown plants often are sold with fewer buds and may take longer to become established.
Deep planting and a shady position can account for a lack of flowers. Consider moving the plant to a more suitable position and/or replant shallower. If moved, it can take a year or two to establish in the new position.
Though established plants are drought tolerant, prolonged periods of drought in spring during the flower bud development can be the cause poor flower bud development and/or the buds failing to open. Mulch around the base of the plant and water during prolonged periods of dry weather.
Peony wilt (grey mould blight) that causes wilting and dieback of the foliage as well as buds and flowers is the only more troublesome disease.
Herbaceous peonies are prone to peony ringspot virus that causes appearance of characteristic irregular yellowish rings on the foliage. This virus generally does not cause major problem to the infected plant and can be tolerated by domestic gardeners. Sterilise secateurs after pruning to avoid spreading the virus from plant to plant.
Peony blotch (Septoria paeoniae) causes grey-brown spotting with red margins on the foliage, but it is not considered a serious problem. There are no specific sprays for this disease.
Dieback and wilting of the may be caused by verticillium wilt.
Honey fungus can cause the decline and death of peonies.
Leaf discolouration, wilting and eventual death may be sign of a leaf and bud eelworm (nematode) infestation. It is a microscopic pest living in the plants’ tissue. It affects foliage as well as flower buds starting on the lower leaves. Blooms may be distorted and stems could show scaring. There is no cure and plants should be destroyed.
Ants may be found on the buds, but the do not cause any damage and can be tolerated.
The foliage can be damaged by various caterpillar pests. Try checking the plant after dark on mild evenings and remove.