Insects That Bother Peonies
Peonies are appreciated for their large and showy flowers, which come in a variety of colors and forms. Generally, peonies have problems with only a few type of insect pests. Most of these insects are simply nuisances and can be easily managed. Severe infestations occasionally occur and can result in stunted growth of the plant, bud failure and root damage.
Scale insects can adversely effect peony plants. They have small gray-brown shells and are little under 1/8 of an inch in length. These insects can be seen on the leaves and stalks of plants in late summer. They suck plant fluids to feed. Small infestations are usually not a problem, though heavy infestations can challenge the plant's health.
Peony thrips are little insects, about 1/16 of an inch long, that resemble flies. The have feathery wings and long tube-like bodies. Peony thrips damage peony leaves, buds and flowers by sucking plant fluids from them. These insects are tiny enough to enter buds and feed. This can cause the buds to fail to open.
Peonies are also attacked by bulb mites. These pearly white arachnids are around 1/32 of an inch long. They feed on peony roots, particularly damaged ones, and often turn the flesh reddish brown. The roots can become soft and may rot from the resulting injury.
Ants are often seen on peonies and, while their presence may be alarming, they actually do no harm to the plant. They are simply interested in the sweet liquid that is secreted by peony flower buds. The only risk from ants is that they might spread diseases, such as the botrytis fungus, by contact.
Peonies Won't Grow
A peony grown from seed will not produce flowers until it is at least 5 years old, and sometimes it takes up to 7 years for a peony to bloom, according to the North Dakota State University Extension Service. For that reason, many home gardeners purchase and plant older peonies. This is because they get crowded. In these cases, dividing the plant should help, but keep in mind that newly divided peonies don't usually bloom the first year after being transplanted. If they are in shade for most of the day, they won't grow or bloom very well, if at all. Dilute the fungicide with water at a ratio of 4 ounces for every 25 gallons of water. To help prevent Botrytis blight and other fungal diseases, water at the level of the soil, keeping the foliage as dry as possible. This is a fungal disease, caused by wet, saturated soil, that destroys the roots of the plant.
- University of Ohio Extension Fact Sheet: Growing Peonies
- University of California Integrated Pest Management Program: Pests in Gardens and Landscapes, Peonies
- North Dakota State University Extension Service: Questions On Peony
- The Old Farmer's Almanac: Peonies
- Heartland Peony Society: Frequently Asked Questions
- University of California IPM Online: Peony (Paeonia spp.)
- University of California IPM Online: Gray Mold Pathogen -- Botrytis cinerea