Divide herbaceous peonies in fall.

1. Decide whether division is necessary

A healthy, well-placed peony can remain undisturbed for years. Division is useful for making more plants or as part of a necessary move; it is not an annual autumn chore. If flowering has declined, first consider shade or excessive planting depth rather than assuming the clump is crowded.

This guide concerns herbaceous peonies, whose top growth dies back. Do not apply the cut-back instructions to a woody tree peony. Check the plant label if you are unsure. The peony growing guide provides the regular planting context.

2. Prepare a site before lifting

Choose a sunny place with well-drained soil and enough room for the mature plant. Use your region's autumn transplanting window. Iowa State gives September for Iowa; that is an example, not a deadline for every climate or hemisphere.

Have labels, a sharp clean cutting tool and the new planting holes ready. When the local timing is suitable, cut back the herbaceous stems and carefully loosen soil around and beneath the root clump. Support the roots as you lift rather than tugging on stems. Remove enough soil to see where the crown, roots and buds join.

3. Count eyes before making a cut

The eyes are the growth buds on the crown. Aim for divisions with three to five eyes and substantial healthy roots attached. A root piece without a viable crown bud is not equivalent to a complete division. Cut deliberately between suitable groups rather than breaking the clump into the greatest possible number of pieces.

• Keep healthy buds and roots together.
• Remove broken or unsound material.
• Clean tools between plants to reduce disease spread.
• Keep the variety label with each division.

Smaller pieces can take longer to build a flowering plant. The University of Michigan botanical garden describes both partial and whole-clump methods; this guide follows the whole-clump route so a beginner can inspect the divisions clearly.

4. Replant at the correct bud depth

For ordinary herbaceous garden peonies in Iowa State's guidance, position the eyes about 1–2 inches (2.5–5 cm) beneath the finished soil surface. Measure from the buds, not from the bottom of the roots. Fill around the roots, settle the soil gently and water. Check local cultivar guidance if your conditions differ.

Follow local advice for temporary winter mulch, and remove it appropriately in spring so the crown does not become permanently buried deeper. Allow establishment time: divisions may need several seasons before a strong flower display. Repeatedly digging them up or adding extra fertilizer is not a shortcut. The autumn care guide helps separate ongoing watering from unnecessary seasonal interventions.