TREE PEONIES AND ITOH HYBRIDS
Herbaceous peonies are part of a larger peony story. Two other important groups offer a glimmer of hope to enthusiasts who don’t have the super-cold climate required for herbaceous peonies. Tree peonies (Paeonia suffruticosa) are slow growing, up to 2m tall. They’re open shrubs with woody stems, which lose their leaves but don’t die down in winter. Slow growing, they have a reputation for being tricky, but don’t need winters quite as cold as herbaceous peonies. The large, open flowers, borne from late September to November, are available in a wider range of colours, including black-red, yellow, orange and coral tones, many with a darker blotch at the centre. They prefer cool to temperate zones and resent hot, dry conditions. Morning sun is best in warmer climates. Tree peonies are sold in pots and best planted in autumn. Be patient, as in the first few years, the blooms can be small, single and not true to colour.
Itoh peonies are named after Dr Toichi Itoh, a Japanese botanist whose life’s work was to cross herbaceous peonies with tree peonies to combine the best attributes of both. Many had tried and failed over decades – the two species flower at different times and genetically are not that closely related. Itoh was the first to succeed. His first seedlings germinated in 1948, but, tragically, he passed away eight years later, before they flowered. His family nurtured the plants until they flowered in 1964, then ensured others could continue their development. Itoh hybrids, sometimes called intersectional peonies, have since taken the peony world by storm. They have exceptional vigour and produce immense flowers in two profuse flushes over an extended season. The plants have the mounded shape of herbaceous peonies, and die down in winter, but they have robust stems that don’t need staking.
The first ones were butter yellow, but they’re now available in pink, white, coral, red and maroon, in single, semi-double and double forms – some as big as dinner plates. They also command high prices, partly because they can only be propagated slowly, through root divisions due to them all being sterile.