The Itoh Peony, formally known as an Intersectional Hybrid, combines the robust structure of a tree peony with the annual foliage cycle of a herbaceous peony. These plants are known for their unique color palette, exceptionally large blooms, and strong, self-supporting stems. Since Itoh peonies are a considerable investment and can live for decades, precise planting techniques are essential for successful establishment. This guide outlines the specific steps necessary to ensure this unique hybrid thrives and produces its spectacular display.
Selecting the Site and Preparing the Soil
Itoh peonies flourish best when receiving at least six hours of direct sunlight daily, which encourages strong stems and abundant flowering. In regions with intense summer heat, light afternoon shade can prevent leaf scorch while still ensuring sufficient energy for bloom production. Placing the plant away from large trees or shrubs is beneficial, as competition for water and nutrients can hinder the peony’s establishment and long-term health.
Proper drainage is crucial for all peonies, as Itoh hybrids are susceptible to root rot if waterlogged. Choose a location where water does not pool after rain to ensure the survival of the plant’s fleshy, tuberous roots. The optimal time for planting bare-root divisions is early fall, typically six weeks before the first hard frost, allowing roots to establish before dormancy. Planting can also occur in early spring once the soil is workable, though fall planting usually results in a more robust first year of growth.
Since peonies are exceptionally long-lived, careful soil preparation is essential. Digging the area deeply and incorporating well-aged compost or other organic matter improves both drainage and nutrient retention. This amendment process creates a rich, friable environment that supports the plant’s extensive root system and its needs as a moderate feeder.
Step-by-Step Planting Depth and Procedure
Planting begins by excavating a hole substantially wider than the peony’s root system, aiming for a diameter at least twice the width of the bare root or container ball. This wide preparation ensures that new, fine feeder roots can easily penetrate the surrounding loosened soil rather than encountering compacted earth. The hole depth should fully accommodate the roots while positioning the crown at the correct height relative to the surface.
When dealing with bare-root divisions, create a small, firm mound of prepared soil at the bottom center of the planting hole. Carefully spreading the roots over this central cone ensures they radiate outward naturally, promoting balanced growth and anchorage. This technique suspends the “eyes”—the small buds on the crown—at the precise level required for successful bloom production.
The depth at which the crown is set is the most important factor determining whether an Itoh peony will bloom. The eyes must be planted shallowly, generally no more than 1 to 1.5 inches below the final soil surface in colder climates, or even less in warmer regions. Planting the crown too deeply is the primary cause of “blind” peonies, which produce healthy foliage but fail to set flowers because bloom initiation is suppressed.
For container-grown Itoh peonies, position the plant so the top of the existing soil line is level with the surrounding garden soil. After positioning the plant correctly, begin backfilling the hole with the prepared soil mixture, working it gently around the roots to eliminate air pockets. Lightly firm the soil with your hands to secure the plant, taking care not to compact the soil heavily, which would impede water infiltration and root growth.
Once backfilling is complete, the soil surface should be gently sloped away from the crown to prevent water from pooling directly against the stems. Applying a layer of mulch around the area helps to regulate soil temperature and conserve moisture. However, the mulch must never cover the crown itself.
Essential Care for New Establishment
Immediately after planting, the Itoh peony requires a thorough watering to settle the soil and remove air pockets around the newly set roots. This initial saturation ensures maximum root-to-soil contact, which is necessary for the plant to begin absorbing nutrients and water efficiently. Monitoring soil moisture for the first few weeks is important, ensuring the soil remains consistently damp but never saturated.
During the initial establishment phase, avoid applying strong nitrogen fertilizers, as this nutrient encourages excessive leafy growth at the expense of root development. If the soil was not heavily amended, a light application of a low-nitrogen fertilizer or bone meal can be scattered around the root zone, well away from the crown, to promote healthy root formation. The plant’s primary focus in its first year is establishing a robust underground network rather than producing heavy top growth.
While mature Itoh stems are typically self-supporting, a newly planted young stem may benefit from temporary staking if it is top-heavy or exposed to high winds during its first season. If the area is prone to severe freeze-thaw cycles, a light layer of loose mulch can be applied after the ground freezes to prevent frost heave. This protective layer must be kept several inches away from the crown to prevent rot or fungal issues during the cold, damp period.
Gardeners should manage expectations regarding bloom production in the first year, as it is normal for a newly planted Itoh peony to produce few or no flowers. The plant prioritizes energy toward building a strong root system that will support decades of future blooming. Patience during this establishment period is rewarded with increasingly vigorous growth and stunning flower displays in subsequent seasons.