The tree peony, Paeonia suffruticosa, differs from the common herbaceous peony by developing a permanent, woody shrub structure that does not die back each winter. This characteristic allows it to grow into a substantial, long-lived specimen, often reaching heights of five to seven feet. Its spectacular, often dinner-plate-sized blooms appear early in the season, preceding herbaceous varieties. Selecting a quality specimen from a reliable source is important due to the permanence and value of mature plants.
Identifying Reputable Retail Sources
The decision of where to purchase your tree peony generally involves a choice between specialty mail-order nurseries and local garden centers. Specialty online nurseries offer the widest selection, including rare and newly developed cultivars unavailable elsewhere. Buying online requires careful research into the vendor’s reputation, checking customer reviews, and investigating their history of correctly identifying plant varieties.
Local garden centers and arboretum sales provide the advantage of physical inspection, allowing you to assess the plant’s health and size. While selection is often limited to common cultivars, these potted plants typically experience less stress than mail-order specimens. When purchasing from any mail-order source, verify their state nursery dealer license, which indicates the business is subject to state inspections for pests and diseases.
Understanding Tree Peony Stock Types
The majority of commercially available tree peonies are propagated through grafting, where a cutting (scion) is joined onto a vigorous herbaceous peony root (nurse root). The nurse root acts as a temporary energy source to speed up establishment. For the plant’s long-term success, the graft union—visible as a slight bulge—must be planted deeply.
Planting the graft union four to six inches below the soil line encourages the scion to develop its own root system directly from the woody stem tissue. Once established, the plant is considered an “own-root” specimen, which is more vigorous and less susceptible to the nurse root dying off or producing unwanted suckers. True own-root tree peonies, grown without a graft, are less common and carry a higher price tag due to the slower propagation process.
Regardless of the stock type, a pre-purchase inspection of a dormant, bare-root specimen should focus on several visual quality indicators:
- The woody stem should be firm and show at least two or three plump, pink or reddish-colored dormant buds, or “eyes,” near the base.
- The roots should feel solid and fleshy, not brittle, dried out, or soft to the touch.
- A healthy root system will be light brown in color, indicating it is free from root rot or excessive moisture damage during storage.
Optimal Timing for Acquisition and Planting
The most effective time to acquire and plant bare-root tree peonies is during their dormant season, typically from fall through very early spring. Fall planting, generally September through November, is preferred because the soil is still warm enough to promote initial root growth before the deep winter freeze. This head start allows the plant to establish itself significantly before the stress of spring growth begins.
If you receive a mail-order bare-root plant when immediate planting is impossible, the technique of temporary “heeling-in” is advised. This involves placing the roots in a shallow trench or a container filled with damp soil or sawdust in a cool, shaded location. The goal is to keep the roots moist and protected from both freezing and drying out until the permanent planting site is ready.
When preparing the permanent location, choose a site with well-drained soil, as the roots are intolerant of standing water. While tree peonies are hardy, they benefit from a location that provides protection from harsh afternoon sun and strong winds. Once planted, settling the soil with water helps the roots make contact with the surrounding earth, minimizing transplant shock.