JARS v59n2 - Companion Plants: Introducing Species Peonies

Companion Plants: Introducing Species Peonies
Leo Smit
Mount Uniacke, Nova Scotia
Canada
Reprinted from the Atlantic Rhododendron Society newsletter, October 2004

There are about thirty-five species of peony identified by various botanists and taxonomists, give or take several species depending upon whose treatment of the genus one wants to go by. The natural ranges of a number of the species are under pressure of one kind or another, and several are rather remote. They occur only in the temperate zone of the northern hemisphere, often at higher (subalpine) elevations; and only two are native to North America. The most recently published reference is that of the Czech botanist and seed specialist Josef J. Halda, The Genus Paeonia , Timber Press, 2004.
While the species peonies do not have the large spectacular flowers that gardeners generally associate with what I call garden peonies, they are nonetheless rewarding and still showy plants in other ways. Their attributes (depending on the species) include shorter stature; strong stems which stand through all weathers; interesting foliage shapes, textures and colours; simple flowers of clean lines, with slightly differing bloom times; lower maintenance requirements; and, in some cases, suitability for shady habitats. So they are, in general, excellent landscape plants providing interest from the first emergence of the leaves until late summer or well into autumn. A garden with a good selection of species plants and named cultivars will have peonies in flower for more than six weeks.
This is in some ways an exciting time to become enthusiastic about species peonies, as the habitats of many are in areas of the former Soviet Union and China which were essentially closed to the west until the early 1900s. Even now some habitats remain fairly inaccessible due to armed conflict resulting from the breakup of the USSR. The new accessibility of some species is accompanied by an element of confusion in nomenclature and lack of English-language reference materials and knowledge of the natural variability of the more wide-ranging species, but this enhances the excitement of growing a plant for several years before really knowing what it is you have!
Culturally, some of the species are quite easy in Canadian climates, while others are more demanding and provide a challenge to experienced growers.

Representative Species
A few words on some representative herbaceous species: (photos and additional information about some species can be found at the Canadian Peony Society website: http://www.peony.ca).

Paeonia lactiflora : This is the historical parent of the majority of named cultivars, descended through many centuries of selection and breeding in China and more recently in the west. It is also involved in the parentage of most of the hybrids. Fragrant and extremely hardy. The wild species is almost never grown, but there have been some recent seed collections from wild populations in remote areas of Mongolia/Siberia/Manchuria, where it grows in dry grasslands and scrub in the mountains.

Paeonia officinalis : This species is native to woods, scrub and rocky slopes, mainly on limestone, in southern Europe, and is classified geographically into several subspecies. A number of named selections, including doubles of different colours, are propagated as cultivars, most notably cultivar 'Rubra Plena' which is a huge double very deep red. Flowers in the species are mainly shades of crimson, up to about 4 inches across. Foliage is attractive, with three terminal leaflets deeply divided into three lobes and tends to dormancy in early fall. Hardy in most of Canada, and fairly easy in good garden soil.

Paeonia veitchii : A nice tidy plant native to alpine meadows, scrub and mountain steppes in northwest China. Flowers are nodding and poppy-like, about 2 inches across, in shades of pink to magenta, sometimes white; with more than one per stem which makes for an extended bloom period; but non-fragrant. Flowering begins about three weeks before the P. lactiflora cultivars, but there is also a late-blooming form. Stems are strong and self-supporting, to about 2 feet tall but reaching nearer 3 feet in wetter summers. Foliage is mid-green, deeply cut and very attractive; on some plants the veining has an etched-like texture. Seedpods of some plants may be tinged with red, and the seeds are bluish while fresh. Quite hardy and easy to grow; suitable for rock gardens and borders. Subspecies woodwardii is similar but about half the height.

Paeonia anomala : Native to coniferous woods, rocky hillsides amongst shrubs, and in dry steppe grasslands over a large range from the Kola peninsula (Finland) through the Urals of Russia possibly into north China (depending on which authority one follows), this species has the most northern range of all. In some respects similar to P. veitchii . Flowers are borne one to a stem (sidebuds may occur in rare instances), upward facing, about 2 inches across, ranging in colour from pink (rarely) to deep magenta and with a silky sheen, sometimes white; non-fragrant; among the very earliest to flower except after warm wet winters, when it flowers somewhat later. Very sturdy upright stems, to about 2 feet tall but may reach 3 feet in deeper shade or during wetter summers. The foliage is shiny green and deeply cut, the width of the segments variable from about inch to 1 inch. Illustrative photos are usually of the finer foliage and darker flowered form. Seedpods are hairy, the seeds black. Very hardy and easy to grow, with some shade tolerance and drought tolerance too. There are a few subspecies and they possibly overlap in appearance with geographically adjacent species.

Paeonia mlokosewitschii : The golden peony. (Worth practicing to get the tongue around the name.) Native to sunny slopes in or on the margins of hornbeam and oak forest in a small area of the southeast Caucasus. Flowers one per stem, to 4 inches across, in shades of yellow varying from ivory to butter-yellow but usually somewhere between; the best known or perhaps only truly yellow herbaceous peony; slight fragrance; blooming about two weeks before the P. lactiflora cultivars. Sturdy burgundy-tinted stems to about 2 feet tall. Foliage very attractive, emerging in burgundy and becoming grayish blue-green, with large rounded leaflets lasting well into the fall and gradually becoming lighter in colour. Interesting seedpods when open: satiny light red lining with small bright red aborted seeds and shiny black or blue-black developed seeds. This plant is traffic-stopping at all stages of growth! It should be growable in most of Canada provided it is irrigated on the prairies and is grown in a sandy soil in the Maritimes; however, there are perhaps some root divisions of non-vigorous plants in circulation. While P. mlokosewitschii is a diploid, there is a tetraploid species P. steveniana which is said to be worth seeking out, but information is only just becoming available.

Paeonia tenuifolia : The fernleaf peony. Probably the most widely grown and available species in Canada after P. officinalis , although it is by no means common. Native to dry grasslands in southeast Europe. Flowers one per stem, to 4 inches across, usually startlingly bright red but varying to magenta; non-fragrant; early blooming, about 2 weeks before the P. lactiflora cultivars. Foliage is extremely finely divided, with segments from 1-5mm wide depending on the plant; bright green in the finest form. The foliage provides outstanding interest from emergence (when it looks like a critter from the pages of Dr. Seuss) until mid-summer or early fall, when it may go dormant, depending on location and climate. Should be fairly easy of culture in most of Canada, but is especially good on the prairies, while in wetter parts of the Maritimes imperfect drainage may cause problems. There are several named cultivars available, including double-flowered forms (at least one of which is a few weeks later to bloom than the species proper) and a pink-flowered form.

Paeonia emodi : A distinctive and attractive plant native to forest clearings in the western Himalayas. Flowers are a pure ice-crystal white, to about 3 inches across, and with side buds on mature plants. The flower is held high over the leaves, outwards-facing; height about 2 to 3 feet. Some descriptions indicate that it is fragrant. Early-flowering, and looks good with blue-flowered companions such as Aquilegia or masses of Myosotis (forget-me-nots). The delicately textured foliage is light green, deeply divided with narrow pointed lobes, and with darker stems; the central veins are narrowly furrowed, with a pale green vein clearly visible. Seedpods deep red/brown. Given its origins and early emergence it may require extra care in sitting in hot and/ or humid regions; I find that morning shade is essential here.
There are several species of tree peonies which have also been eclipsed by more showy named selections and hybrids but which are now experiencing a surge of interest. The hardiest is Paeonia rockii (synonym P. suffruticosa subsp. rockii ) although most of those sold under this name are probably hybrids.

Mr. Smit gardens near Mt. Uniacke, Nova Scotia, which is in the winter snow belt due to the altitude of 650 feet above sea level. He operates El Summit Perennials Nursery with a special emphasis on species peonies.