Herbaceous peonies (Paeonia lactiflora) are perennial plants that die back to the ground each winter and regrow from their roots in spring. Their soft, non-woody stems make them less structurally rigid. In contrast, tree peonies (Paeonia suffruticosa) are deciduous shrubs with woody stems that remain above ground year-round. Tree peonies grow more slowly but can live for decades, even centuries, while herbaceous peonies typically thrive for 50+ years with proper care.
Herbaceous peonies have fleshy, tuberous roots that store nutrients and require shallow planting (buds no deeper than 2 inches below soil). Planting too deep inhibits blooming. Tree peonies, however, are grafted onto herbaceous rootstock and need deeper planting (4–6 inches) to encourage the tree portion to develop its own roots. Their root systems are more fibrous and woody, requiring well-drained soil to prevent rot.
Both types prefer full sun (6+ hours daily), but tree peonies benefit from afternoon shade in hot climates to prevent scorching. Herbaceous peonies are more cold-hardy (USDA zones 3–8) and tolerate frost better. Tree peonies (zones 4–9) are sensitive to late frosts, which can damage their woody stems and emerging buds. In colder zones, tree peonies may need winter mulch or burlap wraps for protection.
Herbaceous peonies demand consistent moisture during their active growing season but are drought-tolerant once established. Overwatering can cause root rot. Tree peonies need deeper, less frequent watering to encourage root expansion. Both require well-draining, fertile soil, but tree peonies thrive in slightly alkaline pH (7.0–7.5), while herbaceous types prefer neutral to slightly acidic (6.5–7.0). Amending soil with compost benefits both.
Herbaceous peonies require minimal pruning: cut stems to the ground in fall after frost to prevent disease. Deadheading spent blooms redirects energy to roots. Tree peonies need selective pruning in early spring to remove dead wood or shape the shrub. Avoid heavy pruning, as they bloom on old wood. Crossing branches should be trimmed to improve air circulation.
Herbaceous peonies benefit from balanced fertilizer (10-10-10) in early spring as shoots emerge and again after blooming. Avoid high-nitrogen formulas, which promote foliage over flowers. Tree peonies respond better to low-nitrogen, phosphorus-rich fertilizers (5-10-10) applied in spring and early summer. Bone meal or compost tea can enhance blooming for both types.
Both are prone to botrytis (gray mold) and fungal leaf spots, but herbaceous peonies are more vulnerable due to dense foliage. Proper spacing and airflow reduce risks. Tree peonies may attract scale insects or borers, which target woody stems. Deer rarely browse tree peonies but may eat herbaceous peony buds. Neem oil or horticultural soap can manage pests organically.
