Family: Paeoniaceae
Common Name: Peony, Paeony

This genus, originating from temperate parts of Europe, China and North America, was formerly considered a member of the Ranunculaceae family, but is now in its own family. Comprising around 33 species, the genus is divided into herbaceous perennials and tree types. Cultivars of the herbaceous plants are mainly derived from P. lactiflora, while the tree peony cultivars are usually derivatives of P. suffruticosa. Both types flower in spring to early summer.

Most of the perennials have large, exquisite, ruffled flowers ranging from pink, mauve and purple to white and yellow, and some have huge, poppylike, single flowers. Both the perennial and tree peonies are widely grown in the US and are among the most popular hardy garden plants. The tree peony originated from China and was introduced into Korea and Japan between the sixth and eighth centuries.

By careful selection, the Japanese tree peony has developed quite differently from its antecedent in China. It has a wider colour range and a more robust character. The tree peony is deciduous in winter; the flowers are similar to those of the herbaceous type, but usually about 30 cm (12 in) across, and may also be single or double. In cultivation the tree peony grows only to shrub proportions, usually reaching 2-2.5 m (6-8 ft) high.

Species

P. delavayi is a tree type, growing to about 2 m (6 ft), with dark maroon flowers.

P. emodi, zone 8, from India, grows to 1 m (3 ftl high, producing single, white flowers.

P. lactiflora, to 1 m (3 ft high, has single, fragrant, white flowers, to 10 cm (4 in) across. Many cultivars have been produced from this species in shades of white, pink, red and purple in single, semi-double and double forms.

P. lutea, from China, has saw-toothed leaves and single, yellow flowers. This tree-type species grows to about 2 m (6 ft).

P. mlokosewitschii, from the Caucasus, grows to 90 cm (36 in), with pale green leaves, hairy on the undersides, that darken with maturity, and single, open, pale yellow flowers, to 12 cm (5 in) across.

P. officinalis, zone 8, from Europe, is believed to have been used medicinally by the ancient Greeks. It grows to 60 cm (24 in), with lobed leaves and single, bright red, rose-like flowers. Subspecies humilis has dark pink to red flowers. Cultivar 'Alba Plena' produces double, white flowers; 'Rosea Plena' double, pink flowers; and 'Rubra Plena', double, crimson flowers.

P. peregrina, zone 8, from southern Europe, has deeply divided leaves and cup-shaped, deep red flowers. It grows to 60 cm (24 in). Many glorious cultivars have been produced from most of the species, and are generally more available than the species.

P suffruticosa, zone 5, from China, bears single, cup-shaped flowers in white, pink, red or purple. Both flowers and leaves are very large. Many beautiful cultivars of this tree type are available.

Cultivation

Plant the herbaceous species in deep, well-drained soil and enrich with well-rotted compost during autumn. They will grow in sun or semi-shade. Propagation is best by division during late autumn or early spring, but they will grow from seed. Plants may remain undivided for up to ten years. Tree peonies will grow in any soil, provided it is well drained. They prefer a sheltered situation. Dress with blood, fish and bone in spring.

Climate

Zone 6, unless otherwise specified below.