October is the best time to add new peonies to your garden or divide older, crowded plants. Planting in early fall gives peony tubers time to become established before winter.
Choose a Good Location
A good site for peonies has well drained, fertile, clay-loam soil and receives full sun or no more than two to three hours of shade per day. Avoid planting peonies within the root zone of trees and shrubs since they will compete with the peonies for water and nutrients.
Peonies also require good air circulation but protection from strong winds. Good air circulation helps control fungus diseases.
Preparing the Site
For best results, prepare the planting site two to four weeks before you intend to plant. Peonies will be in place for many years, so work the soil deep (18 to 24 inches) and incorporate organic matter, such as compost, well rotted manure or peat moss. Adding organic matter will also improve the texture of heavy clay soils and the water-holding capacity of lighter soils. If drainage is less than optimum, consider planting in raised beds.
Dividing Peonies
If you're dividing old plants, dig them up carefully to avoid as much root injury as possible, and remove all foliage. Wash off any soil clinging to the large roots. Then use a sharp knife to divide the crown of the plant, being sure to leave at least three to five pink "eyes" or buds on each section.
For each of these divisions or newly acquired tubers, dig a hole 18 inches in diameter and 18 inches deep. Space holes at least 3 feet apart so plants don't crowd one another. Mix soil from the holes with superphosphate fertilizer and organic matter, add some of the mixture to each hole and water to settle the soil. Then place the divisions or tubers in the holes so that the eyes will be no more than 1 inch below the soil surface when the holes are filled. Add more soil, water again, and then finish filling the holes.
Peonies planted too deep may bloom poorly or fail to come up at all in the spring. If tubers are too close to the surface, the eyes may be killed by frost.
After-planting Care
Water the planting if fall rains are sparse to help the tubers get established before winter. After the ground freezes, mulch the clumps with 2 inches of straw or peat moss and a layer of evergreen boughs or something to hold the mulch in place. The mulch will prevent frost heaving, the alternate freezing and thawing of the soil that can push plants right up out of the ground.
Garden peonies grown from large tubers may bloom in their first year. After that, proper care -- including regular watering, fertilizing and weed control -- should keep peonies producing large, high quality blossoms for 10 to 15 years. Blossoms get smaller as crowding increases.
The author would like to acknowledge the contribution of Don Janssen, former UNL Extension Educator who authored the first edition of this publication.
Feature image by Pixabay.com.