Pruning peonies can help them develop a strong shape and healthy blossoms. It can take place in the spring or fall, although gardeners should be cautioned that pruning in the spring can sometimes reduce the number of flowers for that year. While pruning peonies, it is advisable to inspect the plant for signs of ill-health like fungal infections so these can be identified and treated as early as possible.
In the spring, gardeners can clip back unwanted shoots to help the plant keep its shape and ensure that the base remains well aerated. This can prevent colonization by fungus and insects. In addition, as buds start to develop, gardeners may want to consider pinching back side buds. Managing buds allows the main bud to develop more fully, yielding a showy, large flower. Once flowers have faded, they can be deadheaded to help the plant conserve energy and give it a more tidy appearance.
Fall peony pruning can be more aggressive. Some gardeners prefer to clip their plants back every fall, removing dead or weak branches. About one-third of any unwanted branch can be removed in a year, slowly trimming the plant to a desired shape and size. Alternatively, pruning peonies can take place every three years, when gardeners can cut dead shoots back all the way to the ground. The best option can depend on the appearance of the plant and how well it does in the garden.
People concerned about pruning peonies should know that these plants are relatively resilient. Not pruning at all in the first year is usually recommended to give the plant a chance to get established. As it starts to thrive, pruning can control the shape, which may be important in a more orderly garden. Pruning also helps keep the plant healthy by removing dead, old growth and promoting healthy aeration throughout the branches. Strong branches are also more likely to withstand wind and rain, although staking peonies to support them is also a good idea.
Experts advise using clean shears for pruning peonies. This reduces the risk of passing infections between plants in the garden. Pruning supplies can be dipped in a mild bleach solution after each use to clean them, or they can be treated before use and allowed to dry fully. If gardeners notice signs of disease on a plant, they should be careful about removing the diseased sections and disposing of them appropriately; they shouldn’t be composted, for example, as the organisms might survive and infect other plants when the compost is used.