accepted name (2005)

1992

original description

Paeonia rockii (S. G. Haw & L. A. Lauener) T. Hong et J. J. Li, stat. nov.—

Paeonia suffruticosa Andr. 'Rock's Variety' ( 'Joseph Rock') Hort.—

P. suffruticosa Andr. subsp. rockii S. G. Haw & L. A, Laeuner, Edinburgh Journal of Botany 47 (3) : 273—281 (1990). —

P. suffruticosa sensu Stern, Stud. Gen. Paeonia 40 (1946), p. p.) Fang Acta Phytotaxonomica Sinica 7(4) i 302 (1958), p. p. non Andr.—

P. suffruticosa Andr. var. papaveracea sensu K. Y. Pan, Fl. Reip, Pop. Sin. 27 : 45 (1979), non. Kerner.

Rock's Peony (Paeonia rockii (Haw & Lauener) T. Hong et J. J. Li stat. nov.

It's identified and nominated by S. G, Haw & L. A. Lauener as a new subspecies (P. suffruticosa Andr. subsp. rockii.) based on "Rock's Variety" which was bred from seeds collected by an American Geographer Joseph Rock in 1925—1926 from a peony with big white flower and dark purple basal blotch in a lamasery of Choni County in the south of Gansu Province.

The author of Genus Paeonia of Fl. Reip, Pop. Sin. was mistaken to identify the peony with white flower and dark purple basal blotch which is distributed over the south of Gansu and Mt. Taibai of Shaanxi Provinces etc. as Paeonia suffruticosa Andr. var, papaveracea (Andr.) Kerner.

H. C. Andrews, a British plant taxonomist, studied a peony plant with white flower and dark purple basal blotch, which was introduced to England from Guangzhou, China and cultivated in the garden of Sir Abraham Hume, and identified and nominated it as a new species, Paeonia papaveracea Andr. in 1806, After that, Kerner changed it as a variety, P. suffruticosa Andr. var. papaveracea (Andr.) Kerner in 1816.

Bean, a British scientist, studied the peony planted in Sir Abraham Hume Garden, He thought it is neither a species nor a variety and reduced it as a cultivar, P. suffrulicosa Andr. cv. 'Papaveracea' .

Osti (1997):

Paeonia rockii (S. G. Haw e L. A. Lauener) Hong e Li, in «Bulletin of Botanical Research of Northeastern Forestry Institute», 12 (3), I99-2; è la peonia di Joseph Rock, ben conosciuta nei giardini inglesi da tempo come «Rock's variety». È una peonia diffusa sulle montagne cinesi m condizioni climatiche anche molto diverse fra loro sia come temperatura che piovosità, dal Gansu, in situazione pressoché desertica al Tai Bai Shan nello Shanxi e all'Hubei centrale con precipitazioni più che abbondanti. Questa peonia ha le foglie bi- o tripennate, con 190 fino a 40 foglioline. Se ne possono notare due sottospecie: con foglioline prevalentemente intere, usualmente lanceolate (ssp. linyanshanii) oppure con foglioline prevalentemente lobate e ovate (ssp. rockii). La prima io l'ho vista in natura nell'Hubei, la seconda sul Tai Bai Shan.

Hong Tao (1992)

Paeonia rockii (S.G. Haw and L.A. Lauener) T.Hong and J. J. Li in Bull of Bot. Res. 12(3): 227,1992.

- P. papaveracea Andr.

- P. suffruticosa Andr. var. papaveracea (Andr.) Kerner

- P. suffruticosa Andr. subsp. rockii S.G.Haw and L A Lauener.

This deciduous shrubby species has an erect stem 1.5m high. Leaves on the lower part of a stem are bipinnate with long petioles. The secondary leaflets are long ovate in shape on 2 - 7 primary leaflets. The bottom secondary leaflets are broadly ovate with 3 deep clefts or with none, other secondary leaflets are ovate or ovate-lanceolate. The upper surface is glabrous but soft down is sparsely scattered on the under side and densely along veins. The leaves at the top of a stem are pinnate. One flower only grows on each stem, at the apex. Ten white petals show large dark purple blotches at the base. Filasments pale yellow and flower disc yellowish-white. The 5 to 8 carpels have yellowish-white stigmas. The flowering period occurs in May and the seeds ripen Aug-Sept(Fig.3)

The species is widely distributed in areas with obviously different ecological environments.

(1) The Loess Plateau Forest Area in Shaanxi and Gansu. P. rockii grows in the Ziwuling Forest between the two provinces. This is a temperate semi-humid zone with annual mean temperature 7.4- 8.5°C, maximum 36.7°C, minimum -27.7°C; >10°C accumulated temperature 2600-2700°C; mean annual precipitation 500-620mm; frostfree season 110-150days. The soil is greyish-yellow and spongy or cinnamon-coloured. The plants are scattered in connected belts on northeast or shady mountain slopes undermiscellaneous trees, at an elevation of 1350 to 1510m. The vegetation comprises trees and bushes including Quercus Uaotungensis, Populus davidiana, Betula platyphylla; Cotoneaster multiflorus, Lonicera pekinensis, Elaeagnus umbellata, Lonicera ferdinandii. Spiraea pubescens, Prunus tomentosa. This species once grew in Xinglong and Maxian Mountains of Loess Plateau.

(2) Qinling and Bashan Mountainous Areas. P. rockii has a comparatively wide distribution in the area. Since Qinling Mountain extends for 1000 kilometers, the ecological conditions vary greatly. In the western part in Gansu, P. rockii grows at 1100 to 2800m in broad-leaved forests or forest margins. Around Shaba In Xiaolongshan the annual mean temperature is 6.9°C, maximum 31°C, minimum -22°C; annual mean precipitation 834mm, annual mean evaporation 925.8mm; frostfree season 154 days. The soil is mainly mountain brown earth with pH 6.5.

In the middle part in Shaanxi P. rockii is found on mountain slopes and in woods in Taibaishan Nature Conser-vation District at 1100-1800m. North or north-facing 35-degree slopes and the middle and top parts of valleysare the usual growing places, at the edges of deciduous Quercus forests or miscellaneous trees, or "forest windows" exposed to the sun. Cinnamon or yellow-brown earth with pH 6 - 7. Annual mean temperature 11-14°C, annual mean precipitation 620 -820mm. In other places P. rockii grows in woods, among sparse bushes and in arid rocky cracks on sunny slopes; it is seldom seen in shady and moist gullies.

In the eastern part or in Henan, P. rockii is distributed at 1300-1650m around the main peak of Yangshan. The annual mean temperature in Yangshan is 12°C, maximum 43.6°C, minimum -19°C; annual mean precipitation 821.9mm; frostfree season 170 days. The mountain brown earth has pH 6.43. The average density of the plants is 6 per 100 square metres. (Zhang Yimin, Wang Jintao and Zhang Zanping 1988).

(3) Shennongjia Forest Area Located in the north west of Hubei, Shennongjia is part of the Qinling and Bashan mountainous area extending south east. P. rockii is distributed from 1000-2500m, growing densely at 1000-1600m in sunny open places on wooded hills. Mountain brown earth with pH 5.6-6.3, above 1500m, yellow-brown earth below 1500m. In terms of vertical distribution of vegetation, P. rockii is limited to mixed broad-leaved evergreen, deciduous and coniferous forest zones, with rich plant communities. Annual mean temperature 7.4 to 12.2°C; annual mean precipitation 1000-1700mm; frostfree season 153-224 days. Since P. rocki is distributed in such a wide area with greatly diverse ecological conditions, type differentiation in the species has taken place. Red flowers have been found in Shennongjia, pink and red have been found in Gansu and Shaanxi. Big differences in leaf structure and in form and quantity of leaflets between the north and south can be seen. In Gansu plants have 60-70 leaflets, lanceolate with complete margins.

Sir Peter Smithers on yahoo!groups message #452

The position of this peony has become fairly clear following the researches of
Professor Hong Tao in the wild in China.

The so-called Rock's Peony was introduced from cultivated plants in a lamasery
garden. The Arnold Arboretum in the USA and the garden at Highdown, England
(the late Sir Frederick Stern) were the principal centres of distribution.

The Arnold Arboretum plants proved to be nearer to what is now thought to be the
type than those at Highdown where numerous other Tree Peonies were growing.

In hybridisation the two 'strains' (they are not real strains) tend to produce
somewhat different flowers. the US origin plants tend to have smoother rounder
petals closer to the wild plant. The UK plants have larger flowers with frilled
petals and are perhaps more spectacular. Both are very vigorous growers and I
have never seen botrytis on either in my garden.

When Professor Hong Tao came to my garden a couple of years ago he at first said
that my plant of the US family looked like the right thing. But on taking a
magnifying glass to the flower parts he decided that it showed signs of
hybridity. This probably confirms the notion that other types of Tree Peony
were growing in the lamasery garden from which Rock collected his seeds before
world war II.

It is a fairly safe bet that the true plant is not in cultivation though it is
likely to be introduced from China in the very near future.

However all of that may be, the UK form of this plant is a magnificent parent.
My plant was growing amongst a very large collection of japanese and American
Tree peonies, and I simply collected and sowed the seeds, leaving the choice of
parents to the bees. In due course these produced some magnificent plants, all
with the characteristic brown blotch on the petal bases. Of these several have
been registered with the Registrar and all are illustrated in my book
'Adventures of a Gardener'. They vary in colour from a fine dark red self with
the darker blotches, to lavender mauve, clear pink and a mixture of pinks and
apricots.

A few years ago I sent some of this bee manufactured seed to the chairman of the
Japan Peony Society who distributed it in Japan. Some years later again I was
surprised to hear from him that one of the seedlings resulting, a lavender mauve
similar to my registered 'Luella', had won 'best seedling of the year' in Japan.
I cite this as one is normally reluctant to claim anything for ones own
products. However, in the light of that event I can certainly reccommend
anybody who has a good form of what is called Rock's Variety, particularly if it
has nicely frilled flowers which are not typical of P.rockii, to use it as a
parent with good Japanese or American plants.

Looking at some of the modern American hybrids I have no doubt that their
breeders have used the Arnold Arboretum plants in their breeding. I think,
however, that the UK plants give better results, though my US type plant has
given some very elegant smooth rounded flowers.

My own parent plant os both forms are now at the Riviere Nursery in France,
along with 104 of my Japanese and American Tree Peonies, and all of my named
hybrids from 'Rock'. Old age is closing in and I was anxious to preserve my
work. The Riviere firm has been breeding Tree Peonies since their first
introduction from China in the last century and is now in its sixth generation
in the family. As I have no financial interest in this matter, and as the
plants were a gift to Riviere, I can with a clear conscience give the address
for anybody interested in them:-

Pivoines Riviere, La Plaine, 26400-Crest, France
Fax:- 33 (04) 7576-7738

They put out a very beautiful illustrated catalogue and sell nothing but
peonies. However not all of my 'Rock' hybrids have yet been propagated in
sufficient numbers to be available for sale.

Peter Smithers

Sir Peter Smithers

Sir Peter Smithers on yahoo!groups message #490

Jim

There is nothing wimpish about the colour of Tree Peony Regent. It is a
stunning brilliant orange with a slightly pink shading. Perhaps the most
outstanding Tree Peony colour in the garden, where we have grown about 150
different cultivars, and massive great flowers.
I got mine from the late Miss Saunders. Riviere is propagating it as
hard as he can go.

Peter