Peonies are best cut back in autumn after the leaves have changed color and started to die back, not while they’re still green. The general rule is to trim herbaceous and Itoh/Intersectional peonies down to about ground level (roughly 2–3 inches) once the foliage has faded, often following the first frost in many regions. Woody tree peonies are not cut back; they’re only lightly pruned to remove dead or diseased wood and to shape, if desired. Key guidance by type:
- Herbaceous peonies: Cut back after the first frost and when foliage is mostly yellow or brown. Trim to about 2–3 inches above the soil. Do not compost the leaves if disease is suspected; dispose instead. This timing helps reduce disease pressure and prepares the plant for vigorous growth next spring.
- Intersectional / Itoh peonies: Often cut down to the ground each fall, similar to herbaceous types, to maintain a tidy frame and promote strong next-season growth.
- Woody/tree peonies: Do not cut back to the ground. You can trim away dead or damaged stems and lightly shape after flowering if needed.
Timing considerations:
- Local climate matters. In cooler regions, late autumn after frost is typical. In milder or warmer climates, you might prune a bit later in fall after the leaves have faded.
- Avoid cutting while leaves are still green and actively feeding the plant; doing so can remove stored energy the roots need for next year.
Practical steps:
- Use clean, sharp pruners.
- Remove spent flowers and any diseased leaves/stems promptly.
- Dispose of pruned material rather than composting if disease is present.
- Mulch lightly in spring after new growth begins to emerge.
If you’d like, share your hardiness zone and whether you grow herbaceous, Itoh/intersectional, or tree peonies, and I’ll tailor the timing and exact cut-back height to your location.
