Peonies (Paeonia spp.) are traditionally associated with the cold winters of northern climates, as they require a substantial period of winter chilling (vernalization) to initiate flowering. Southern U.S. states, characterized by hot, humid summers and mild winters, present a significant challenge for many herbaceous peony varieties. The primary obstacles include insufficient chilling hours, intense heat that can scorch blooms, and high humidity that promotes fungal diseases like botrytis. Therefore, selecting the right type and variety is critical for success.
While standard garden peonies (Paeonia lactiflora) often struggle, certain hybrid varieties bred from species native to warmer regions of Europe and Asia show remarkable adaptability. The most important group for southern gardeners is the Hybrid Herbaceous Peonies, specifically those derived from Paeonia officinalis and complex crosses that include Paeonia peregrina and Paeonia tenuifolia. These hybrids are celebrated for their tolerance to warmer winters and earlier bloom times, which allows them to flower before the most intense southern heat arrives.
Several specific cultivars have proven their merit through extensive trialing in southern conditions. Their plant physiology allows them to thrive with fewer chilling hours and resist common fungal pathogens.
'Festiva Maxima' (Paeonia lactiflora): A classic white double peony with crimson flecks. It is one of the more heat-tolerant lactiflora varieties and remains a reliable, though not guaranteed, performer in the Upper South if provided afternoon shade.
'Kansas': This variety boasts vibrant rose-red double flowers. It is known for its strong stems and better-than-average heat tolerance, making it a robust choice for gardens where summers are intense.
'Sarah Bernhardt': Perhaps the most famous pink double peony. While it prefers cooler climates, it can perform well in the Upper South (USDA zones 7b-8a) if planted in a location with morning sun and afternoon shade to protect the blooms.
Intersectional Hybrids, or Itoh peonies, are crosses between herbaceous and tree peonies. From a botanical standpoint, they combine the strong, woody structure of a tree peony with the die-back habit of an herbaceous peony. They are exceptionally well-suited for the South due to their superior heat tolerance, incredible disease resistance, and incredibly sturdy stems that require no staking. Their foliage remains attractive throughout the season, and they often produce a second flush of growth after blooming.
'Bartzella': A spectacular Itoh variety with large, fragrant, yellow double flowers. It is highly resistant to peony blight and thrives in the heat and humidity of southern states.
'Garden Treasure': Another outstanding yellow Itoh, prized for its prolific blooming and vigorous growth habit. It handles the climate challenges of the South exceptionally well.
'Cora Louise': This variety features large, semi-double white flowers with a striking lavender-purple flare at the base. It is a vigorous and disease-resistant plant perfect for southern gardens.
Selecting the right variety is only the first step. Providing the correct growing conditions is paramount. Peonies must be planted in a well-draining soil amended with organic matter. In the South, planting them in a location that receives morning sun and afternoon shade is ideal to protect the flowers from scorching. Ensuring good air circulation around the plants is critical for preventing fungal diseases. A deep, thorough watering once a week is preferable to frequent light watering. A light layer of mulch can help keep the root zone cool but should be kept away from the crown of the plant.
