Itoh peonies represent a significant advancement in the world of garden plants, bringing together desirable traits from two distinct peony types. These hybrids offer a unique combination of beauty and resilience, making them a valued addition to many landscapes. This article will explore what defines Itoh peonies, their specific characteristics, proper care techniques, and the benefits they offer to gardeners.
What is an Itoh Peony
Itoh peonies are known as intersectional hybrids, a classification that describes their unique genetic makeup as a cross between herbaceous peonies and tree peonies. This hybridization was considered a challenging horticultural feat. The first successful creation of these plants is credited to Toichi Itoh, a Japanese horticulturist, in the 1940s. His goal was to develop a peony that combined the strong stems and broad color palette of tree peonies with the herbaceous growth habit that dies back to the ground in winter.
Before Itoh’s work, truly yellow double-flowered herbaceous peonies did not exist, and yellow blooms were primarily found on woody tree peonies. Itoh spent decades attempting thousands of crosses to achieve this specific outcome. While he passed away in 1956 before seeing his creations bloom, his dedication led to the development of 36 yellow seedlings that would later flower. This breakthrough in hybridization opened up new possibilities for peony breeding, expanding the available color range and combining the best attributes of both parent types.
Key Characteristics of Itoh Peonies
Itoh peonies exhibit characteristics from both their herbaceous and tree peony parents. They form a mounded, bushy growth habit, reaching 2-3 feet in height. Their stems are strong and self-supporting, inherited from tree peonies, meaning they do not require staking.
The foliage of Itoh peonies is deeply lobed and dark green, resembling that of tree peonies, and remains attractive throughout the growing season until autumn. Unlike tree peonies, their stems die back to the ground in winter, similar to herbaceous peonies.
Itoh peonies have an extended bloom period, lasting up to three or four weeks, longer than most herbaceous peonies. This is due to their ability to produce multiple buds, with side buds opening after the initial terminal blooms. The flowers are large, up to 8 inches across, and come in a wide spectrum of colors, including yellow, coral, pink, red, and white. Some varieties feature flares at the petal base or change colors as they age.
Caring for Itoh Peonies
Itoh peonies thrive in full sun to partial shade, requiring at least six hours of sunlight daily. While full sun promotes dense foliage, some light shade can help prolong bloom duration.
Itoh peonies prefer well-drained, rich soil with a neutral to slightly acidic pH. Improving soil with organic matter like compost enhances its structure and nutrient retention. Consistent moisture is important, especially during establishment, but avoid overwatering to prevent root rot.
When planting bare roots, position the “eyes” or growth buds 1 to 2 inches below the soil surface. Plant slightly deeper for colder zones and shallower for warmer ones. Deadhead spent blooms and cut back foliage to the ground level in late autumn once it has died back.
Advantages of Growing Itoh Peonies
Itoh peonies offer several benefits for gardeners. Their strong, sturdy stems, inherited from tree peonies, eliminate the need for staking. This allows their large blooms to be displayed without support, even after rain.
The broad color palette of Itoh peonies, including yellow and multi-toned flowers that evolve over time, offers diverse aesthetic choices. Their extended bloom period, lasting several weeks, prolongs the display of flowers in the garden.
Itoh peonies also resist common diseases, contributing to their hardiness. Once established, these plants require minimal care, making them a reliable, long-lived garden addition.