Also known as Intersectional Hybrid Peonies, these wonders are a cross between herbaceous garden peonies and tree peonies and feature the best of both.
Named for Toichi Itoh, the Japanese hybridizer who supposedly made thousands of attempts to cross garden and tree peonies. He finally succeeded in 1948 but did not live to see his seedlings bloom. In the 1970s Toichi’s widow gave an American breeder permission to introduce Itoh peonies to the West, where hybridizers took up the intersectional torch.
Giant 6-9" blossoms (like the ones on tree peonies) open right after the garden peonies have faded. The growth habit is similar to garden peonies with attractive mounded foliage that dies back in the winter. But do not cut Itoh peonies down the ground in the fall—next year’s buds need room to develop on the lower stems. Leave at least 6" of hardwood stems above the ground.
Herbaceous Perennial Plants
When you receive your order, open the bags and check the stock immediately. Roots and crowns should be firm and pliable. Surface mold is harmless and will not affect the plant’s future performance. Store plants in their packaging in a cool (35–40°) location until you are ready to plant. If it’s going to be awhile, you can pot up your perennials.
Do not plant bare-root perennial plant crowns directly outdoors before danger of frost has passed. Wet and/or cold conditions for an extended period may cause rotting.
For more info:
About planting bare-root perennials.