Peonies are herbaceous perennials that are favored both for their flowers as well as their foliage. The plants produce large blossoms between late spring and early summer in shades of yellow, red, pink and white. The plants reach a mature height of 2 to 4 feet. Peonies are rarely bothered with pests and problems. However, some common insects that are likely to inflict peonies are scales, ants and bulb mites.
Scales are the only insect of any consequence to the peonies. Scales are tiny insects that attach to the plant stems and hide under brown or gray oval shells. The insects often look like a bunch of oysters. Scales insert sucking tubes into plant stems and feed on the juices. If scale growth is not checked in time the insects multiply very rapidly and can render serious damage to the plant. Scales belong to the same family as aphids, whiteflies and mealy bugs. The treatment of scales is relatively simple as the bugs can be rubbed off with a rag or the blasted from hose water.
Bulb mites attack the fleshy rooted perennials like peonies and daylilies. Bulb mites resemble large clusters of white pepper grains and lead to stunted growth of the plants. The insects are very small and adult bugs are only about 1/25-inch. The mites never come above ground. The plants most susceptible to bulb mites are the ones with rotted and damaged bulbs. Once the mites infect the sick plants they quickly spread to the healthier plants as well and cause the growth of bacteria and fungi too. It is easy to control bulb mites in the earlier stages with special pesticides for bulbs. However in the advanced stages the only option is to destroy the entire plant. The soil also needs to be treated before new plants are placed in it.
Ants are often found in large number of peonies but their presence is neither harmful not beneficial for the flowers. The ants are most often attracted by the sugary liquid secreted by the flower buds. If there is any concern regarding the presence of ants of peonies it is for the spread of diseases such as botrytis fungus through contact.