How to grow peonies: choose the type and plant at the right depth

Peonies can look extravagant without needing an extravagant routine. Their large flowers make a short but memorable display, while healthy foliage continues to hold a place in the border afterward. The most important work is choosing the right plant and setting it at the right depth.

Do not treat every peony as the same sort of perennial. Herbaceous plants, intersectional hybrids and woody tree peonies have different structures. Knowing which one you have prevents both deep planting and an unfortunate autumn encounter with the pruning shears.

Herbaceous peonies die back above ground and send up new shoots from their crowns. Intersectional, or Itoh, peonies also lose their top growth; they are not evergreen shrubs for winter foliage. Both can provide substantial clumps in a sunny border.

Tree peonies are woody shrubs. They normally lose their leaves but retain a framework of branches. Do not cut them to the ground as though they were herbaceous. Check the named cultivar’s ultimate size, flowering season and local hardiness, and allow space for the mature plant rather than judging by a small spring pot.

Herbaceous and intersectional peonies generally perform best in full sun with fertile, well-drained soil. A position crowded by large roots or shaded by expanding shrubs can reduce flowering. Tree peonies may appreciate some protection from strong afternoon exposure, depending on climate and variety.

Improve unsuitable soil structure before planting, while avoiding a water-holding pocket in poorly drained ground. A plant can tolerate a range of soil textures without tolerating standing water. Place supports early for heavy-flowered varieties, so the growing stems can fill them naturally instead of being tied into a tight bundle after rain.

For bare-root herbaceous divisions, the eyes or growth buds need only a shallow covering of soil. Common recommendations fall around 2.5–5cm (1–2in), with the precise depth following local guidance and the supplier’s instructions. Too-deep planting can prevent flowering even when foliage looks healthy.

Potted herbaceous plants should not be buried beneath a new mound of compost. Keep mulch from gradually covering the crown more deeply each year. Grafted tree peonies have different planting-depth requirements; use the instructions for that plant rather than applying the shallow herbaceous rule to every peony.

Autumn is a useful time for planting bare-root divisions in many climates. Plants sold in pots can be planted during suitable growing conditions with adequate follow-up care.

Water new plants through dry spells while roots establish, and keep an eye on moisture during active growth. An established border plant and a peony in a container will not dry at the same rate. Feed moderately if soil conditions justify it; more nitrogen is not a reliable route to more flowers.

Remove spent flower heads if seed is not wanted, but retain healthy leaves to support the plant. In autumn, remove dead herbaceous foliage. Preserve the living woody stems of tree peonies and follow their lighter pruning requirements. Do not apply a general fungicide automatically as part of a calendar routine.

Keep the name with the plant so its growth habit remains clear after the foliage has died.

A peony with plenty of foliage but no buds presents a different puzzle from one whose buds swell and then turn brown. Record which happened before moving the plant or buying a bloom booster. The failed stage helps narrow the investigation.

There were no buds. Revisit the crown's depth, the amount of light and any recent division. Pulling mulch back can reveal how much material has accumulated above a herbaceous crown. Photograph the position before making a correction; do not dig around the roots every spring to check whether last year's adjustment worked.

Buds appeared, then shrivelled. Look for damaged shoots, brown tissue and the timing of a cold or wet spell. Purdue Extension's peony guide describes Botrytis-related bud and shoot damage, but a brown bud alone does not establish the cause. Late cold, insufficient light and other stresses can also affect development. Photograph the whole plant and a close-up of the affected part before asking a local diagnostic service.

Flowers opened, then collapsed after rain. Heavy double blooms may simply need earlier support. A support placed while stems are short allows them to grow through it; tying a wet, fallen bundle upright usually makes a much less comfortable-looking plant. If that annual job is unwelcome, flower form belongs on the selection list alongside colour.

Ants are another observation, rather than a treatment target. They visit sugary secretions on peony buds, and flowers can open without them. Purdue advises against using insecticides to manage those visitors. For a vase, inspect and gently shake cut stems outdoors before carrying them inside.

Keep healthy leaves after flowering, remove diseased debris appropriately and note the season's result. One failed display does not necessarily justify dividing an otherwise sound, recently established clump.

If a peony fails to flower, check planting depth, light, competition and how recently it was moved. A newly divided plant can take time to settle; repeated disturbance is unlikely to hurry it. Inspect damaged stems or leaves and identify the problem before choosing a treatment.

Divide an established herbaceous clump when there is a reason, commonly in autumn, keeping healthy crown sections with roots and growth buds. Seed is slower and usually does not reproduce a hybrid exactly. Peonies can be long-lived, but they are still living plants with different regional requirements—not a guaranteed century of flowers in any available corner.