How to Grow Paeonia
Commemorating Paeon, an ancient Greek physician, said to have first used P. officinalis medicinally. Although the genus has long been considered a member of the buttercup family, Ranunculaceae, some modern botanists now place it in a family of its own, Paeoniaceae. A genus of 33 species of hardy herbaceous and shrubby perennials and a few shrubs, among the noblest and most decorative plants for a sunny or shaded border. The main division of the genus is between the herbaceous and the tree paeony, but botanically the matter is much more complex. Stern's monograph, A Study of the Genus Paeonia, published by the· Royal Horticultural Society in 1946, deals with the whole classification. The wild herbaceous species are single-flowered and vary in height from about 1 foot up to 3 or 4 feet. The double varieties have been developed by breeding and selection. The tree paeonies, although woody shrubs, are deciduous and are often grown in association with other hardy perennial plants. They enjoy a sunny position but are liable to be broken by summer gales so should be planted in a reasonably sheltered place. Long established specimens-they live many years-may attain a height of 7 feet or more with a considerable spread. Accordingly it is necessary to allow ample space when planting tree paeonies for no paeony likes being moved once it has been planted. Tree paeonies are often grafted on to the rootstock of P. officinalis, the common garden paeony, and when plant ing, care should be taken to bury the point of the union between the stock and the scion 3 inches below the surface. It is at this point that a young specimen may get broken in rough weather. If possible choose a site that does not get the early morning sun because tree paeonies come into growth earlier than herbaceous varieties and the young shoots may be damaged by late spring frosts.
Species cultivated P. anomala, 1.5 feet, foliage finely cut, flowers bright crimson, May, Russia, central Asia. P. bakeri, 2 feet, flowers purplish-red, May, possibly of garden origin. P. broteri, 1.5 feet, purplish-red, May, Spain and Portugal. P. cambessedesii, 1feet, deep rose·pink, April-May, Balearic Isles, liable to damage by spring frost. P. clusii (syn. P. cretica), 1 foot, white, May, Crete. P. coriacea, 1 -2 feet, rose, April, Spain, Morocco. P. delavayi, up to 5 feet, shrubby, dark red, May, China; var. angustiloba, leaves finely divided. P. emodi, 1-3 feet, white, May, Himalaya. P. humilis,15 inches, distinct small leaflets, dark pink to red, May, southern France, Spain. P. lactiflora (syns. P. albiflora, P. edulis), up to 2 feet, white, fragrant, June, Siberia, northern China, Mongolia. P. lutea, shrubby, up to 4 feet, yellow, June, China, Tibet. P. x lemoinei (P. lutea x P. sutfruticosa), shrubby, 4-5 feet, flowers large, yellow, May-June, hybrid race. P. mascula (syn. P. corallina), 2-3 feet, deep rose, May, Europe, naturalised in Britain. P. mlokosewit schii, 1feet, foliage, grey-green, flowers yellow, coral stamens, April, Caucasus. P. of/icinalis, up to 2 feet, red, May, southern Europe; vars. alba-plena, the old double white paeony; rosea plena, the old double rose paeony; rubra plena, the old double crimson paeony. P. peregrina (syns. P. decora, P. lobata), up to 3 feet, deep maroon-red, May, southern Europe, Asia Minor. P. potaninii (syn. P. delavayi angustiloba), shrubby, up to 5 feet, deep maroon, May, western China. P. sutfruticosa (syn. P. moutan), tree paeony, up to 6 feet, rose-pink, May, China, Tibet. P. tenui folia, 1-2 feet, leaves finely dissected, fern-like, flowers deep crimson, May, Transylvania, Caucasus. P. veitchii, 1-2 feet, purplish-red, June, China. P. wittmanniana, up to 3 feet, yellowish, April, Caucasus.
Hybrid Double Paeonies (a selection)
'Adolphe Rousseau', 3 feet, maroon,
golden anthers, large, June. 'Alice Harding', 2 feet, pale pink, cream within, fragrant, excellent foliage on strong stems, May and early June.
'Baroness Schroder', 3 feet, free flowering, white, with yellow centre, large globular blooms excellent for cutting, fragrant, late May and June.
'Claire Dubois', 3 feet, satiny pink and silver, June. 'Duchesse de Nemours',
3 feet, free flowering, white to pale sulphur-yellow, medium-size, incurved bloom, fragrant, May and June. 'Edulis Superba', 3 feet, old rose-pink, edged silver, fragrant. Early May onwards, much used as a commercial variety for cut bloom. 'Eugene Verdier', 3 feet, soft pink, silver-edged, free-flowering, a famous old variety, June. 'Felix Crousse', 2feet, bright deep carmine, large, a popular variety. 'Festiva Maxima', 3 feet, pure white, flecked crimson, fragrant, a splendid old variety, the name meaning the largest and gayest, May. 'Germaine Bigot', 2feet, semi-double, glistening white, shaded pale salmon, fragrant,· June. 'Karl Rosenfeld', 2§ feet, bright crimson, June. 'Kelway's Glorious', 2 feet, creamy-white, large, fragrant, among the best of the doubles, May-June. 'Sarah Bernhardt', 2} feet, bright pink, tipped silver, large, June.
Hybrid Single Paeonies 'Eva', 2 feet, deep salmon-pink, June. 'Lady Wolseley', 2 feet, deep rose, large, June. 'Lord Kitchener', 3 feet, deep maroon-red, May. 'Pink Delight', 2 feet, pale pink, becoming white, May.
Cultivation Paeonies are easily grown in sun or partial shade and in deep fertile soil, preferably containing lime, where they can remain undisturbed for many years. Top dress with old ma nure or garden compost in February every two or three years. Named varieties of herba ceous a nd tree paeonies are in creased by division in September or October, which gives the newly-planted pieces time to make fresh roots before the ground is f rozen. Great care must be ta ken when lifting the clumps for division, as the thick root-stock is very brittle. Paeonies ca n be raised f rom seed, but it is a slow process and the seedlings may vary considerably in colour arid form. Seed should be sown
about 2 inches deep in sandy loam in a cold frame in September. Newly gathered
seed is best. With old seed the covering may be hard and the seed should be soaked in water for a few days before sowing. Some seeds may germinate the first spring, but the majority may take up to two years. Placing seed in a refrigerator for 48 hours or so before sowing sometimes· accelerates germination. Seedlings .may take five years or more to develop into plants large enough to produce mature blooms. One cannot assess accurately the quality of the blooms from those produced in the first and second year of flowering as they are not usually typical. Grafting in August is done by commercial growers, usually on to stock of Paeonia albiflora. Tree paeonies can also be layered, but it is a slow process, and air layering has been attempted on a small scale without great success.