Tree peonies (Paeonia suffruticosa) and herbaceous peonies (Paeonia lactiflora or other species) belong to the same genus, Paeonia, but differ significantly in growth habit. Tree peonies are deciduous shrubs with woody stems that persist year-round, growing taller each season (up to 4–7 feet). In contrast, herbaceous peonies are perennial plants with soft, green stems that die back to the ground in winter and regrow from the roots each spring, typically reaching 2–4 feet in height.
Tree peonies develop thick, woody stems that become more robust with age, often living for decades or even centuries. Their stems remain upright during dormancy, forming a permanent framework. Herbaceous peonies, however, produce tender, herbaceous stems that wither annually. Their longevity relies on underground storage organs (roots and crown), which can also survive for many years but lack the woody structure of tree peonies.
Tree peonies have larger, deeply lobed leaves with a leathery texture and a glossy surface. The foliage often turns bronze or purple in autumn before dropping. Herbaceous peonies feature smaller, finely divided leaves with a softer texture and a matte finish. Their leaves emerge in a reddish hue in spring, mature to green, and yellow before dying back in fall.
Both types produce showy, fragrant flowers, but tree peonies bloom earlier (mid-to-late spring) and bear larger flowers (6–12 inches in diameter) with a wider range of colors, including yellows and purples rarely seen in herbaceous varieties. Herbaceous peonies flower later (late spring to early summer) with slightly smaller blooms (3–6 inches), predominantly in shades of pink, white, and red. Tree peony flowers are often held above the foliage on sturdy stems, while herbaceous peonies may require staking to support their heavy blooms.
Tree peonies develop a deep, woody root system with a slow growth rate, making them challenging to propagate. They are often grafted onto herbaceous peony roots. Herbaceous peonies form fleshy, tuberous roots that divide easily for propagation. Division is the primary method for herbaceous peonies, whereas tree peonies are typically propagated by grafting, cuttings, or seed (which may take years to flower).
Tree peonies are less cold-hardy (USDA Zones 4–9) and prefer sheltered locations to protect their woody stems from winter damage. Herbaceous peonies thrive in colder climates (Zones 3–8) and tolerate harsher winters, as their top growth dies back naturally. Both types require a winter chill to bloom but differ in their tolerance to extreme temperatures.
Tree peonies need minimal pruning—only dead or weak wood should be removed in early spring. They are drought-tolerant once established but benefit from mulch to protect roots. Herbaceous peonies require cutting back to the ground in fall to prevent disease and promote healthy regrowth. They demand well-drained soil and regular watering during active growth.
Tree peonies are generally more resistant to fungal diseases like botrytis due to their woody stems and better air circulation. Herbaceous peonies are prone to foliar diseases, especially in humid conditions, and may attract ants (which are harmless but often mistaken for pests). Both types can suffer from root rot if overwatered.
