Tree peony(Paeonia suffruticosa 'Zhao Fen')

Overview

Tree peony ‘Zhao Fen’ (Paeonia suffruticosa ‘Zhao Fen’, traded in Western horticulture as Zhao’s Pink or Pink of the Past) is one of the four legendary classic Chinese tree peonies bred in Luoyang during the Qing Dynasty. Hardy in USDA Zones 4 through 8, this slow-growing woody deciduous shrub reaches 3 to 5 feet tall and wide. In mid-to-late spring, it produces immense, highly fragrant, multi-petaled crown- or double-form blossoms measuring 6 to 8 inches across. Blooms open in soft peach-pink and mature into luminous porcelain-blush white petals accented by golden stamens.

Unlike common herbaceous peonies (Paeonia lactiflora) that die down to the ground each winter, tree peonies form a permanent woody skeleton that persists above ground through freezing temperatures, providing architectural winter interest.

How to Grow

• Sunlight & Siting: Full morning sun with dappled afternoon shade is ideal. In warm southern zones (Zones 7 and 8), afternoon shade is essential to prevent hot sun from bleaching the delicate pink blossoms and shortening bloom life. In northern zones (Zones 4 and 5), provide shelter from sweeping winter winds.
• Deep Planting for Grafted Stock: Most commercially purchased tree peonies are grafted onto herbaceous peony rootstock. When planting, set the graft union (the swollen joint where scion meets rootstock) 4 to 6 inches below the soil surface. This deep planting protects the graft from freezing and encourages the woody scion to develop its own vigorous root system.
• Soil & Drainage: Requires fertile, humus-rich, neutral to slightly alkaline soil (pH 6.5 to 7.5) with sharp drainage. Tree peony roots rot quickly in heavy, waterlogged winter soil.
• Watering: Water deeply during spring establishment and bud swelling. Established shrubs develop deep taproots and show moderate drought tolerance.

Landscape Uses

• Aristocratic Spring Specimen: Functions as a majestic focal point near entryways, sheltered courtyards, and patio terraces where its sweet rose fragrance can be enjoyed.
• Mixed Shrub & Perennial Border: Anchors perennial beds alongside late-spring bulbs, providing handsome, deeply divided green foliage that lasts until autumn frost.
• Historic Asian Garden Design: An essential classic element in Chinese, Japanese, and contemplative courtyard gardens.

Potential Problems

• Herbaceous Rootstock Suckers: If vigorous green shoots with smooth leaflets emerge from below the graft union, remove them immediately at the base so the rootstock does not outgrow the woody cultivar.
• Pruning Mistake Alert: Never cut woody stems down to ground level in autumn. Tree peonies bloom on old woody stems; cutting them down destroys next spring’s flower buds. In late winter, prune out only dead twigs back to an active green bud.
• Fungal Blight (Botrytis): In wet, humid springs, gray mold can cause bud blast. Space shrubs generously to ensure good air circulation and water at the soil level.

Frequently Asked Questions

Is ‘Pink of the Past’ the same as ‘Zhao Fen’?

Yes. ‘Pink of the Past’ is the common English horticultural trade name for the classic Chinese cultivar ‘Zhao Fen’ (Zhao’s Pink).

Do tree peonies need to be cut down in the winter?

No. Unlike herbaceous peonies, tree peonies are woody deciduous shrubs. Cutting them down in autumn will eliminate all flowering wood for the coming year.

How deep should I plant a grafted tree peony?

Set the graft union 4 to 6 inches beneath the soil line. This deep planting prevents suckering from the herbaceous nurse root and encourages the woody tree peony stem to root on its own.

Companion Plants

Complement tree peony ‘Zhao Fen’ with companion plants that share its demand for fertile, well-draining soil and appreciate sheltered light:

• Spring Flowering Partners: Pair with late-blooming Darwin hybrid tulips, Siberian squill, or bleeding hearts (Dicentra spectabilis).
• Groundcovers Under Canopy: Underplant with creeping phlox (Phlox subulata), sweet woodruff (Galium odoratum), or low-growing epimediums.
• Summer Foliage Contrast: Plant adjacent to maidenhair ferns, dwarf conifers, or broad hostas for summer texture after peony petals drop.

Sources & Lineage

• Missouri Botanical Garden PlantFinder: Record taxon 251415 (Paeonia suffruticosa ‘Zhao Fen’ ZHAO’S PINK) — morphological baseline and hardiness record.
• American Peony Society (APS): APS Peony Registry & Cultivar Database — cultivar heritage, bloom form classification, and cultivar synonyms (‘Zhao Fen’ / ‘Pink of the Past’).
• Kew Plants of the World Online (POWO): Paeonia suffruticosa Andrews (POWO: 519067-1) — botanical taxonomy and accepted species status.