What Pot to Use for Peonies

Transplanting

• Peonies are temperamental plants that don’t respond well to transplanting, warns North Carolina State University's Department of Horticulture website. The plants may stop flowering for years after transplanting. Divide and transplant peonies only if they stop producing well. If you must disturb them, transplant your peonies in September, and plant newly obtained peonies in fall if you hope for them to flower the following year.

Type

• Select a porous container made of clay or wood to allow air to penetrate to the roots of your plants and to prevent issues with over-watering. Select non-porous pots if you live in a location that will experience freezing temperatures in the winter, as porous pots are more likely to be damaged by temperature changes. The containers must offer good drainage to prevent the plants from developing fungal diseases or root rot.

Size

• Peonies require a large planter. They are deep-rooted plants that are typically set 12 to 18 inches deep in a space offering at least 18 inches of room to spread. Peonies reach 2 to 4 feet tall, and their heavy flowers often need support. While the Ohio State University Extension recommends a 3-foot diameter area for each plant, you can place them in smaller containers. However, this means they will outgrow their containers faster and have to endure more frequent transplants. In a pot of sufficient size, peonies will happily remain for the long term in the same container -- up to 15 years before needing division.

Considerations

• Using containers to house your peonies allows you to place the plants where they can receive better sun exposure, but if you use large-sized containers, they will likely become a near-permanent fixture once you place them, so evaluate your site carefully. The plants need full sun, and you can locate them near a support structure if you prefer not to use the type of supports that sit inside the containers.

Soil

• Using a medium without soil will spare you some of the weight in your filled containers, and prepared potting mixes and soilless growing media will eliminate competition from weed seeds and exposure to some soil-borne diseases found in yard soil. These forms of growing media are also less likely to become compacted.

Temperature

• Peonies need cold temperatures to flower and are adapted to USDA hardiness zones 2 to 8, but your pots might not be able to withstand freezing temperatures. You may need to either bring the containers indoors, or add insulation to protect the pots and plant roots, and mulch your plants to offer protection from temperatures below minus 20 degrees Fahrenheit.