Carsten Burkhardt's Web Project Paeonia - The Peony Library

ano_finnland7 index 0602 boreas2



The ornamental value of all the various plants in cultivation known as Rock’s peony is not in dispute. All who have seen or grown them attest to the incomparable beauty of the huge (up to 9 ins/22.5 cms diameter) white blooms, often flushed with pink on opening, with the characteristic large, reddish or purplish-black blotches at the bases of the petals and a great deal of ink has flowed in their praise. The often repeated story of its discovery in China by the American plant collector Joseph Rock is usually based on the account in Sir Frederick Stern’s monograph A Study of the Genus Paeonia, published in 1946. Stern’s information was, in turn, mostly derived from a letter he received from Rock in 1938, large sections of which are quoted in this work. Rock recounts how he collected seeds from plants growing in the courtyard garden of the Yamen (official residence) of the lamasery of Choni (modern spelling Zhouni) in SW Gansu which he says he occupied “for about a year”. (In fact, as will be seen, he used it as a base from which to explore the surrounding area for almost two years). No date is given for the collection in the letter, although Rock does mention that the lamasery was “entirely destroyed and the lamas all killed in 1928 by the Mohammedans, so the plant (sic) does in all probability not exist any more as the entire Lamasery was burned to the ground”. It is rather curious, therefore, that Stern should have stated that Rock sent seed to the USA “ some time after 1932”, although by the time he published A Chalk Garden in 1960 he had revised this to 1926. However, this appears to be just one of a number of errors, ambiguities and half-truths attributable to both Stern and Rock, which subsequent authors have faithfully repeated right up to the present time. To be fair to Stern, the problem then and to a certain extent today, was the dearth of information concerning the collection and dispatch of the seed from Choni, its arrival at the Arnold Arboretum and its subsequent distribution to other interested parties. As will be seen, some twelve years were to elapse between the original receipt of the seed and Stern’s first sight of the incredible flowers in 1938. Only then was he galvanised into trying to trace the details of its origin. Enquiries to the Arnold Arboretum no doubt received the same reply then as today – there were no records of any tree peony seed received from Rock, even though meticulous records of every other wild collection he made, together with his field notes were and are available. Fortunately, we have discovered enough evidence from other sources, notably Rock’s original diaries at RBG Edinburgh, previously unpublished correspondence between Rock and his sponsors now available on the Arnold Arboretum web-site, Stern’s papers at RBG Kew as well as the accession records in the archives of both Kew and Edinburgh, to be able to piece together the full story of the introduction of Rock’s peony into western gardens.

Dr Joseph Francis Charles Rock (1884 -1962)

Born in Vienna, Austria in 1884, Josef Franz Karl Rock quickly developed an extraordinary linguistic ability and by the age of sixteen had mastered a number of foreign languages including Arabic, Chinese and Latin. In 1905, a year after gaining his degree at Vienna University, he emigrated to the United States where he increased his proficiency in English, which language he used for all his subsequent writing. In 1913 he became a naturalized citizen and anglicized his name to Joseph Francis Charles Rock. As a young man Rock suffered from tuberculosis and went to Hawaii in 1907, where he remained until 1920 and regained his health there. During this stage of his career he thoroughly explored the islands and developed a comprehensive herbarium of the native flora and published a number of authoritative books and scientific papers. To his friends and colleagues he was known as Pohaku, the Hawaiian word for rock. His reward for his dynamic efforts culminated in his appointment as Professor of Systematic Botany at the College of Hawaii in 1919. In between he also found the time to undertake several plant introduction journeys, including a round the world trip in 1913/14 and others to Malaysia in 1916 and 1919 and to Southern California in 1917, all at his own expense.

With his reputation as a scientific botanist and plant explorer now secured, Rock finally left Hawaii in 1920 to spend the next three decades in active research and exploration in Asia. During this period he was to introduce thousands of Asiatic plants (including 439 species of Rhododendron alone) to the United States and to gather many more thousands of botanical, ornithological and zoological specimens, as well as taking over forty thousand photographs and mapping previously unknown regions. As well as the recently named Paeonia rockii, numerous other plants, birds and mammals commemorate his name. From his base in Li-chiang (now Lijiang) in the Chinese province of Yunnan he made a comprehensive study of the Na-khi (now Naxi) people and translated many volumes of their literature, later publishing a two- volume dictionary of their language. Although perhaps not as well known, at least in the UK, as some of the other plant hunters of the first half of the twentieth century, there is no doubt that Rock ranks as their equal in many respects and is clearly superior in others.

Charles Sargent and the Arnold Arboretum

During the early years of his travels in Yunnan and neighbouring parts of Burma, Siam and Indo-China, Rock’s chief sponsors were the US Department of Agriculture and the National Geographic Society. In the summer of 1924, he returned to Washington D.C. and called upon the elderly Professor Charles Sprague Sargent, Director of the Arnold Arboretum at Jamaica Plain, Boston, Massachusetts. Sargent, who was to be a key figure in our story, had previously employed the by now famous English plant collector Ernest (“Chinese”) Wilson to collect seeds of woody plants for the arboretum, mainly in the more southerly provinces of Hupeh (now Hubeh), Szechuan (now Sichuan) and Yunnan. Many of these introductions did not prove hardy enough to withstand the cold Massachusetts winters, so Sargent was keen to find tougher species or forms from the mountain ranges farther north. Wilson, who had suffered a nasty accident whilst returning down the Min Gorge in Szechuan after collecting thousands of bulbs of Lilium regale in September 1911, had long since retired from active exploration and was now working at the Arnold under Sargent. The latter quickly recognised that Rock was the man he was looking for to undertake an expedition to the Amne Machin (now Anyemaqen Shan) and Richtofen (now Datong Shan) ranges on the borders of Kansu and Tibet (both are now included in the modern province of Qinghai). The Arnold Arboretum expedition, to be sponsored by Harvard University, was to take three years and Rock (salary $500 per month and a similar amount for expenses) immediately began to purchase essential equipment and instruments prior to setting sail from San Francisco bound for Shanghai in the first week of October 1924.

Expedition to Kansu (now Gansu)

Essentially, the expedition started from Yunnanfu (now Kunming), the capital city of Yunnan, where Rock arrived in early November 1924. This was one of the most unsettled periods in China’s turbulent history and fighting and brigandage was rife throughout the province. In addition, the north-east was stricken by famine and many peasants were dying of cold and hunger. It was December 13th before Rock and his caravan of twenty-six mules, porters, trained Na-khi staff and heavy military escort were finally able to set out on their long journey north.

The details of this four-month, danger-ridden journey through the Chinese badlands, initially following the ancient caravan route via Chaotung and Suifu to Chengtu (Chengdu), where Rock had to delay for a month until the route became safe to continue, then on via Mienchow (Mianyang) and across the Kansu border to Kaichou (Wudu), Minchou (Min Xian) to Choni, need not concern us here. They are recorded faithfully in Rock’s copious diaries and also in the numerous letters he wrote to Sargent and others at the Arnold. Suffice to say that only someone of his stubborn determination, tenacity and bravery would have even contemplated such a venture let alone successfully accomplished it. He and his caravan eventually reached Choni on April 21st 1925. Choni, a village of some four hundred families and roughly 2000 inhabitants, according to Rock, lay in the valley of the Tao River, a tributary of the great Huang Ho (Yellow River), at an altitude of 8000 feet. It was the centre of a semi-independent Tibetan principality of the same name which was ruled over by a hereditary prince called Yang Chi-ching. Rock described it thus: “The village is by far the best situated spot in Kansu Province, and the Prince’s territory, which I traversed from north to south and east to west, is the choicest bit of land. Nowhere else in Kansu are there such forests, and the scenery is unsurpassed”. Prince Yang (his actual title was t’ssu – chief or headman) was in his mid thirties and was a cruel and rapacious leader by all accounts who treated his subjects abominably (he was later horribly murdered by his own people after Rock had left), but nevertheless proved a good friend to Rock, helping him with letters of introduction, procuring supplies and pack animals and even lending him money. As he was also the Grand Lama of the nearby lamasery he was able to provide Rock with comfortable accommodation in part of the yamen there. The lamasery, it should be noted, was situated on a plateau about five hundred feet above and slightly to the west of the village. It was said to be the third largest of its kind and was almost a village in itself, with 172 buildings plus a further ten large and small chanting halls within its walls. Around 700 “malodorous” monks were in residence at the time, although as many as 3800 had been present in earlier years. The Prince and his family resided in his own palatial yamen down in the village itself.

In spite of this promising start, Rock, who had anticipated being well clear of the troubles affecting Yunnan and Szechuan, was disturbed to find that he had merely exchanged one set of problems for another. Here in Kansu and along the borders with Tibet and Szechuan there was fighting between the Mohammedans and the local Tibetans as well as hostile tribes such as the Tebbus and the Ngoloks to contend with; such problems were to severely hamper his plans to get to the ranges he had come to explore. (It should be noted that Tibet at that time included much territory that is now included in the modern provinces of Qinghai, Gansu and Sichuan) Rock, therefore, decided to make Choni his base for the remainder of the expedition, returning at the end of each foray into the surrounding mountains and valleys and spending the next two winters writing up his field notes and sorting, labelling, packing and then dispatching the seed harvest to Sargent at the Arnold Arboretum. He finally left Choni for the last time on March 10th 1927.

(At this point, having sketched out the background, we can return to the story of Rock’s peony. The interested reader who wishes to learn more about the fate of the remainder of the expedition may do so by consulting any of the references given at the end of this chapter. Recommended are the articles by Rock published in the National Geographical Magazine and S. B. Sutton’s book In China’s Border Provinces).

The Courtyard Garden and its Peonies

It will be recalled that Rock, in his letter to Stern dated 30th August 1938 (the original is to be found amongst Stern’s papers in the archives at Kew), stated that “The seed of the Paeonia about which you enquire I collected from plants which grew in the Yamen of the Choni Lamasery…” Rather confusingly, he later refers to “the plant” and several times to “it” as if there was only one plant, at least of this particular kind. On the other hand he also wrote that “There were no double-flowered ones, all were single”, without making it clear whether they were all the same. Further evidence of the presence of peonies there occurs in one of Rock’s articles for the National Geographic – “Life Among The Lamas Of Choni” in which he refers to “a tiny courtyard filled with choice peonies, lilacs and other flowers.” In the letter to Stern he mentions that “I took a photo of it growing in the court and I enclose a copy with my compliments”. This photograph (a black and white print) was subsequently used by Stern to illustrate an article entitled “The Moutan Paeony” which appeared in the Journal of the Royal Horticultural Society for December, 1939. It shows the whole garden, which appears to be no more than perhaps twenty by thirty feet in size. According to Rock’s diary, it is likely that this photograph was taken on May 18th 1925. Unfortunately, it is rather grainy and it is not possible to make out too much detail, but most of the plants do look like peonies, some of which are in flower. However, it appears that there is only one plant, which by its shape and stature and the poise of its flowers could be a tree peony of the P. rockii type. It is not certain whether the other plants are tree peonies or herbaceous kinds. The photograph is missing from Stern’s file at Kew, but we have seen the original print which (along with 20,000 others) is held at Edinburgh.

The reason we draw attention to the question of the number of plants of the kind from which the seed was collected and whether other different tree peonies were also present is because this has an important bearing on whether the seed could possibly have been true P. rockii to start with. Rock gave his view in the letter to Stern; “I remarked at the time that it looked to me like a wild species. The lamas told me it came from Kansu, but whence, the exact locality, they did not know. I never came across it in a wild state. It had been kept for years in the Lamasery.” Stern, it should be noted, in the Journal of the Royal Horticultural Society in 1959 and also in The Chalk Garden (1960) slightly embellished this by stating that “The Lamas told him that it came from the mountains of Kansu…” He and others, including Haw and Lauener, who described and named P. rockii (as P. suffruticosa ssp rockii) for the first time in 1990 seem to have accepted without question that plants in cultivation raised from the original seeds sent back by Rock belong to the wild species. Our view is that there are other much more plausible explanations. Although it is conceivable that the original plant(s) in the lamasery were transplanted there from a wild source and could, therefore, have been true P. rockii, the seeds produced would only be true if no other kinds of tree peony were present either in the same small garden or anywhere else nearby. There is some evidence, at least from plants in cultivation, that isolated plants or clones are self sterile, so if there was only one plant of P. rockii to start with, as appears likely from the photograph, it might well have been pollinated by some other tree peony. What is much more likely to have been the case anyway, in our opinion, is that the plant(s) were of hybrid origin to start with, bearing in mind that it is known that the Chinese have been cultivating, hybridising and selecting Ziban Mudan (literally Purple-Spotted Tree Peonies) for centuries past, especially in Gansu, and that such plants were not uncommonly planted near temples and monasteries. In fact we shall go on to show that we believe that all the plants in cultivation that have derived directly or indirectly from Rock’s seed are merely examples of Gansu Mudan.

The Prince’s Garden

It seems best to include this section here, before we leave Choni, even though chronologically it is one of the most recent parts of the story that has emerged during our investigations. In all the accounts of Rock’s peony that we have read, no one has ever referred to the garden of the Prince of Choni or the role its peonies might have played in this complex tale. Other than in his field notes, the only mention by Rock himself that we have found was in a letter to Sargent dated December 13th 1925. Right at the end of a long account of the seeds collected that autumn he casually remarked “I have also seeds of several Paeonia grown by the Prince of Choni. These are tall plants and he says they come true to seed”. The field notes, which are preserved in the accession records at both Kew and Edinburgh, are typed, presumably from Rock’s handwritten originals and there are three separate collections that refer to tree peonies, all included right at the end of the list and without collector’s numbers. One was said to be from the lamasery garden of Choni and is presumably the one that has been under discussion so far; the other two were both said to have come from the “Choni Prince’s Yamen”. It will be recalled that the prince’s yamen was situated down in the village, five hundred feet below the lamasery. The significance of these two collections from the prince’s garden will become apparent in due course.

There is one other point that should be highlighted here. In his letter to Stern, Rock stated that he collected the seeds from the plant(s) in the lamasery garden. The collection date given in the field notes for all three of the tree peonies was simply “October 1925”. Now, Rock’s diary clearly shows that he was away from Choni from August 13th until December 3rd, so it would seem highly unlikely that he collected any of the seeds personally. This may not be of any significance, since Rock used a number of trained Na-khi collectors, although it does beg the question as to how he seemed to know, on receipt of Stern’s enquiry as to the origin of the seed, which garden it had come from.

Rock recorded in his diary that he completed the labelling of seeds harvested that autumn together with corresponding herbarium specimens and despatched them to the Arnold Arboretum on December 15th 1925. The tree peony seeds were sent at the same time, but unfortunately without any specimens as far as is known.

Arrival and Departure

Rock’s seeds, including those of the tree peonies, arrived at the Arnold Arboretum on the 12th February 1926. They must have been dealt with very promptly, because a letter addressed to the Director of Kew dated the 19th of that month and signed by Charles Sargent, advising of the dispatch of 151 packets of Rock’s seeds, was date stamped on the 28th. The same letter was sent to Edinburgh, the only difference being that they were sent 148 packets and no doubt all the other recipients were treated similarly. Enclosed with each letter was a typed copy of Rock’s field notes and a handwritten check-list with details of the collection numbers of all the seeds in that consignment; all that is, except for the peonies, which had no numbers and were added on at the end. In fact, the Arnold does have the international distribution records of this and other Rock seed consignments, together with the total number of packets sent to each recipient, but not the details of exactly which seeds were sent where, so it is not possible to tell from their list who received any of the peony seed. Stern, in his monograph, rather strangely we think, included an incomplete list which he and others have repeated in subsequent accounts. Strange, because we know he was in possession of a more extensive list at the time. The evidence for this is contained in a copy of a letter sent to him by a friend from Montreal who also happened to be one of the original recipients. His name was F. Cleveland Morgan who, as will be seen later, was another major player in our story. Stern must have contacted Morgan early in 1938 seeking information as to who else might have received some of the original seed. Morgan, in turn, wrote to the Arnold and received two letters in reply dated 5th and 6th May from William H. Judd. Judd worked at the Arnold for thirty years from 1920 to 1950, at least for part of that time as propagator and is commemorated in Prunus x juddii and Viburnum x juddii. In the first letter he mentions that Charles Sander, who was gardener to Professor Sargent, had raised two plants “from the same lot of seed as yours” and that they had flowered in Sargent’s garden at Wollaston, Massachusetts. He also wrote that the colour of the petals was “pale lilac” and that there were two sheets from these two plants in the herbarium. In this letter he said that he did not know of any one else who had received seed, but the very next day he wrote again to say that he had found others who had also been sent seeds. The full list given in the second letter was:

Royal Botanic Gardens Kew, UK

Royal Botanic Gardens Edinburgh, UK

Berlin-Dahlem Botanic Garden, Germany

Bergianska Botanical Garden Stockholm, Sweden

Professor A. P. Saunders, Clinton, New York

T. A. Havemeyer of Long Island, New York

Lionel de Rothschild, Exbury, UK

F. Cleveland Morgan, Montreal, Canada

Professor C. S. Sargent

We also have evidence from another source that Kenneth McDouall of Logan, Scotland was another recipient and this will be discussed later.

Germination Results

As far as we can discover, only a very small number of plants was raised in total by the ten known recipients. Of course, we can only guess at the amount of seed there was to start with. If there had been say, 100 seeds of each of the three collections, then each recipient would have received only ten seeds of each one, supposing that each had been sent all three collections. That this was not necessarily the case, we know, because the list of contents sent to Kew shows only two, whereas Edinburgh was sent all three. Surprisingly, we can find no evidence that any plants at all were raised at either Kew or Edinburgh. At Kew, there is no record of sowing, although other collection numbers from the same consignment do appear in the propagation records. At Edinburgh, there is a pencilled note against one of the lots on the contents list which reads “Did not germinate”, but that is all we could find. At Kew there are several plants in the garden erroneously labelled Paeonia rockii or something similar, but we have checked their accession records and none have any direct connection with Rock’s seeds. At Edinburgh, there is an interesting plant labelled P. suffruticosa ssp. rockii which is believed to have originated at Logan and is probably a seedling or perhaps even a clonal propagation from an original Rock seedling – more of this later. There is no doubt that the seeds were viable, since plants were successfully raised elsewhere. As the seed coats would have been dry and hard on receipt, it is doubtful if any would have appeared above ground until the following spring at the earliest, so perhaps the seed containers were thrown out too soon; but one would have thought botanic garden staff were experienced enough to know that. However, it should be borne in mind that literally thousands of packets of seeds were pouring in to these places at the time and it is understandable that some may have been neglected or not even sown at all.

Of the remaining recipients, we have no knowledge of any plants being raised by Rothschild, Saunders or Havemeyer. It might have been expected that Professor Saunders, an acknowledged authority and breeder of both tree and herbaceous peonies would have been the most likely to have succeeded, but a thorough perusal of his many contributions to the American Peony Society Bulletin right up to the time of his death in 1953 has yielded nothing. If he had raised plants, he surely would have used them in his breeding programme and there is no evidence of this as far as we know. Those who were successful will now be looked at individually.

Professor Charles Sargent (1845-1927) / Charles Sander

The riddle of the role of Sargent and the Arnold Arboretum in this part of the story has long puzzled researchers, including ourselves. It perplexed Stern for years; indeed, right up to 1967 when he died, aged 82. There is a letter amongst his papers at Kew dated in that year that shows he was still trying to solve it even then. In fact, as will be seen, that letter contained a vital piece of information that neatly concluded this line of investigation. Why were there no records at the Arnold of Rock’s peony seeds or the plants which surely the arboretum must have raised? The first glimmer of an answer came when we discovered from the check-lists that accompanied the consignments sent from the Arnold to Kew and Edinburgh that the three lots of peonies did not have collection numbers. This would explain why they were missing from the original handwritten, numbered notes that Rock sent back with all the other collections. Apparently, Rock took with him a set of notebooks with pre-numbered pages in which to record the details of each collection, but obviously the peonies were not included. Why were the peonies not given a number like everything else? We can only guess that the most likely reason was that they were collected from a cultivated rather than wild source. However, we know from the typed version of the notes that were sent out from the Arnold to Kew, Edinburgh and, presumably, the other recipients, that Rock did send brief notes about the peonies, which must have been separate from the rest. What happened to those notes? The only explanation that fits the facts is that Sargent took them home along with the seeds of the peonies. This was probably not the first time that he had done this with seeds that he considered were of horticultural rather than scientific interest. When Judd’s letter came to light confirming that Charles Sander, Sargent’s gardener, had raised two plants from the original seed the glimmer became a full moon! Sadly, Charles Sargent died in 1927 so would probably have known nothing of Sander’s success. We calculate these plants would have first flowered in 1932 or 1933, as Judd, in his letter of the 5th May 1938, refers to having raised a batch of seedlings from them “which are not yet large enough to flower.” (Stern, in his monograph, inferred that all the original seedlings first flowered in 1938, another error that has been repeated down the years). Judd’s comment about the colour of the petals being pale lilac is interesting, but we will not dwell on it here. He may only have been referring to the colour on first opening which is often pale pink before changing to white.

The trail has gone cold over what happened to Judd’s seedlings. Again there appears to be no record of any finding their way into the arboretum. It is possible that they were destroyed by rodents, but we have not been able to confirm this. For a long time we puzzled over the fate of the original two plants. Sargent’s estate was sold after his death and has since been built over. Then we found the letter referred to above in Stern’s file at Kew that seems to give the answer. It was from Leo J Armatys, of Sampson & Armatys, Attorneys at Law, from Central City, Nebraska, who was an amateur peony breeder and, we must assume, a friend of Stern, and dated 16th February 1967. Apparently, at Stern’s request, he had written to the Director of the Arnold Arboretum “for information as to Rock’s Variety”, and mentions that he had received “several interesting letters from them”. He goes on to say “Their records do show two tree peonies grown from seed sent by Rock from Tibet. One was 481-29, from Sargent’s estate and the other was 907-36 from Charles Sanders (sic) – but both plants died”. There seems little doubt that these were the two plants discussed above. The letters from the Arnold to Armatys could be interesting to say the least, but our attempts to find out from the Arnold whether they still have copies of them have been unsuccessful.

F. Cleveland Morgan (1881 – 1962)

Of all the characters in this saga, Frederick Cleveland Morgan is the least known; yet the significance of the part that he played cannot be over-estimated. Even his friend Stern never referred to him by name in any of his published writings. In fact the only clue as to his identity comes from a hand-written note on Stern’s garden record card for Paeonia suffruticosa. Cleveland Morgan, who had studied Natural Sciences at Cambridge University, was a wealthy businessman who had an estate at Senneville on the Island of Montreal, Canada. Part of his estate now forms the Morgan Arboretum of McGill University. He collected fine art from all over the world, but was also well-known in horticultural circles for his interest in rock gardening and as a breeder of bearded iris. It was probably the latter which originally linked him with Stern who was also keen on iris. Exactly when they first met is not known, but they were both present at a conference about “Rock Gardens and Rock Plants” in London on May 5th, 6th and 7th 1936, organised jointly by the Royal Horticultural Society and the Alpine Garden Society, where Morgan gave a paper entitled “Rock Gardening in the Province of Quebec”. It was probably here, during dinner with Lord Aberconway on the Tuesday evening, or perhaps in the hotel bar afterwards, that Stern first learned of Morgan’s involvement with Rock’s peony and it cannot be mere coincidence that he duly received a specimen of the peony “from a friend in Canada as quite a small plant in the autumn of 1936” (JRHS, 1959). The note on the record card confirms that the donor was Cleveland Morgan of Montreal and the date as November 1936.

Having discovered that Morgan had received some of Rock’s seed from the Arnold in 1926, we had great difficulty in finding out what became of it. Enquiries in Canada have failed to locate any of his diaries or correspondence and it seems his name is all but forgotten in horticultural circles there. However, by the greatest bit of good fortune and the interest and diligence of the librarian at Montreal Botanical Garden, a letter dated January 27th 1941 from Morgan to Henry Teuscher, the designer and first curator of the garden, was found in the archives. The two were obviously in the habit of exchanging plant material and in it Morgan wrote “The few seeds of Peony suffruticosa are worth trying as it is very rare and only now becoming known. I grew my one plant from seed sent me by the Arnold Arboretum and collected by Rock in Tibet over ten years ago”. Cleveland’s granddaughter Elizabeth Morgan, who still lives in the old family home, ‘Le Sabot’ in Senneville, has confirmed that the plant no longer exists there. It will be noted that there was a gap of over ten years between Morgan’s receipt of the seed, almost certainly in March 1926, at the same time as the other recipients, and November 1936 when he sent a young plant to Stern. The significance of this will be discussed later. What is believed to be the original plant still survives in Stern’s old garden at Highdown, near Goring-by-Sea, Sussex.

The Bergius Botanical Garden, Stockholm

We have not yet had the opportunity to visit the Bergius Botanical garden ourselves and, again, have experienced some difficulty in obtaining the proof that we would like to see regarding the fate of the seeds sent to them in 1926. For most of what we know we are indebted to Tom La Dell, a landscape designer from Kent who formerly worked at the Bergianska as a student in the 1970’s. La Dell became interested in this subject following an article by Stephen Haw in The Plantsman (September 1991) in which he described the petals of “Paeonia suffruticosa ‘Rock’s Variety’” as “more or less pure white, sometimes slightly tinged pink” (this was based on the plant at Highdown which Haw & Lauener believed, wrongly we suspect, to be an original from Rock’s seed). La Dell remembered that plants he saw growing in the Bergianska in his student days and which were said to have been raised from Rock’s seed, varied from light to dark pink in colour and none was white. This concurred with several reports we had received about pink-flowered plants of Rock’s peony in other gardens in both Sweden and Norway. La Dell returned to the Bergianska in October 1991 and examined the accession records which showed that six plants had been raised from seed received from the Arnold Arboretum in 1926, of which four were still living. The most recent (2005) information we have is that only two still survive. Critically, the records also show the origin of the seed to have been the “Prinsens av Choni trädgården” (the Prince of Choni’s garden). It will be recalled that two of the three seed lots were from the Prince’s garden. Reference to Rock’s field notes for these collections reveals the following:

Paeonia sp. Shrub 4-5 ft. tall, fls very large, white.

Paeonia sp. Shrub 4-5 ft. fls very large, red.

Both lots were described as “grown in the garden of the Choni Prince’s yamen, Choni, elev. 8500 ft. October 1925.”

Interestingly, there was no mention of blotches, but neither was there in the description of the third lot from the lamasery garden. Now it can be seen that an explanation for the pink-flowered plants raised at the Bergianska becomes possible. Either they were derived from the batch of seed from the red-flowered plant (we suspect it was probably some shade of pink), or, even if from the white-flowered plant, this would almost certainly have crossed with the red one and if the red colour was dominant the resulting seedlings would all flower some shade of pink. Curiously, from what we understand, plants of subsequent generations always flower pink, whereas, even if the white colour was recessive, one would expect it to appear eventually. Karl Evert Flinck, the respected Swedish horticulturist, in a letter to Tom La Dell dated 21st May 1992, reports that “I have planted probably a thousand seeds (from the Bergianska plants) over the years and never had any white flowering plants. There have been plants that have flowered very pale but not clear white as the Rock form does”. We have evidence from a catalogue of the Bergianska nursery dated 1939 that plants raised from seed taken from the six originals have been distributed since at least that year and this no doubt accounts for the pink-flowering plants to be found in Scandinavian gardens today.

In answer to the question as to whether either or both of the plants in the Prince’s garden could have been examples of true P. rockii from a wild origin, our view is the same as for the plant(s) in the lamasery garden. However, it should be pointed out that Chinese botanists (Wang Lianying et al. 1998) claim to have found pink and red-flowered plants in the wild, but it is not yet clear if this has been generally accepted. In any case, it seems best to regard all the plants raised at the Bergianska from Rock’s seed and subsequent generations as belonging to Gansu Mudan.

Berlin-Dahlem Botanic Garden

Again, we have not yet been able to visit Berlin to see the peonies for ourselves and we are indebted to Gärtnermeister Rolf Marquardt, a retired former curator of the botanic garden for the information which follows.

Unfortunately, we understand that no documentary evidence exists at Berlin to prove that the plants there are derived directly from Rock’s seed. Apparently, the files containing the records were destroyed in 1974 after becoming damaged by mould. However, if Marquardt’s opinion is accepted, Berlin not only had the highest germination of any of the recipients of Rock’s seed, but also has by far the highest number of surviving plants today. A detailed report prepared by him in May 2002 indicates that there could be as many as thirty plants with single flowers varying from pure white to wine-red and with the characteristic blotches that are considered to be originals. According to Marquardt, “It has always been the case that the plants here today, at least seventy years old, are of the first generation Rock provenance and none are of the further offspring sown later in European, American or New Zealand gardens”. The wide variation in colour would seem to indicate that the plants derive from at least two of the three seed lots sent back by Rock. Differences in the colour of the anther filaments are also noted, with variation from white to red and in two cases the colour of the sheath surrounding the carpels is also red. These are clear signs of hybridity and again we have no doubt that all these plants are Gansu Mudan.

Kenneth McDouall of Logan, Scotland (1870-1945)

Logan, a sub-tropical garden a few miles north of the Mull of Galloway, became part of RBG Edinburgh in 1969; prior to that it had been owned privately. The garden was effectively created by Kenneth McDouall and his brother Douglas during the first half of the last century. Kenneth was an outstanding plantsman who was well-known in the leading horticultural circles of his day and would have acquired new plants from many sources, including sponsoring the expeditions of contemporary plant hunters such as E.H. Wilson. It will be recalled that McDouall was not on the list of recipients supplied by Judd and the only indication of his involvement comes from a remark by Stern in the December 1939 article he wrote for the JRHS. Rock, who was then living in Kunming, towards the end of his letter to Stern dated August 24th 1938, wrote “If you have any seed to spare of this beautiful Paeonia, I would appreciate if you would send me a few seeds by registered letter to ensure their arrival. I should like to plant them in my garden.” In the article Stern stated “It may be interesting to record that seeds of this Paeony kindly sent to me by Mr K. McDouall of Logan, were sent to Dr Rock in China to replace the plants destroyed in the Lamasery at Choni and were safely received by him, so let us hope the Paeony will again bloom in the lamasery in years to come to bring peace and joy to the monks.” Ignoring the blatant embellishment, the fact that McDouall was able to supply the seed suggests that he had been growing the peony for some time; at least, longer than Stern himself, whose plant had only flowered for the first time that year. The puzzle of where his plants came from took a long time to solve.

The Plant Database of the Royal Botanic Garden, Edinburgh, under the name Paeonia suffruticosa S. G. Haw (the author should be Andrews), includes five specimens under their accession number 19599781 which are stated to have been collected in China by Joseph F. Rock. Four of these are growing at Logan and the other at the main garden in Edinburgh. This latter plant, which is said to have originated at Logan, was moved to its present site in 1987 from the garden of Professor D. M. Henderson, former Regius Keeper, when he retired. When RBG Edinburgh took over Logan it is said that there were no records relating to the garden and its plants and the only evidence of the origin of the tree peonies came by word of mouth from the older staff there. For a long time we searched in vain for evidence that would link the Logan plants with the Arnold Arboretum and Rock. At first we were convinced that McDouall must have obtained them as seed or seedlings from Edinburgh, in the knowledge that the latter had received some of the original seeds; but a careful search of the dispatch records there proved fruitless. Having seen the plants at Logan in flower in 2003, we thought they were slightly pinker than usual and turned to the Bergianska as a possible source, but still could not find the link. Finally, a misfiled letter in Stern’s papers at Kew provided the answer. It was from Kenneth McDouall to Stern and dated May 16th 1938. McDouall wrote “The seed of this peony came from Wilson, from America. It was collected by Rock whom I remember described it as a beautiful species with a large flower. The seed was taken from a plant growing in a monastery garden which Rock came across on a collecting expedition in China. I do not know the year but it was some time ago. I do not think the seed had a number when it came here.” Wilson, it will be recalled, was working for Sargent at the Arnold when Rock’s seeds arrived and obviously knew Kenneth. In fact, Barrie Unwin, the current curator at Logan, has confirmed that Wilson is known to have visited Logan.

We have seen the four plants at Logan and in our opinion, judging by their present size and locations, they are unlikely to be the originals raised from Rock’s seed. The one at Edinburgh looks from its size to be much older, but is still most unlikely to be an original plant. It may have been a seedling from an original, or even perhaps a layer or rooted cutting from one, but it is unlikely that we shall ever find out. One thing is fairly clear though – to Kenneth McDouall and Logan must go the honour of being the first in the UK to flower Rock’s peony, almost certainly well before 1938.

This completes the review of all those known to have received some of the original seed from the Arnold Arboretum. To the best of our knowledge, apart from the thirty or so plants at Berlin-Dahlem, and the two survivors at the Bergianska in Stockholm, which can be considered to be originals even in the absence of any absolute proof, all the other plants in cultivation today known as “Rock’s Variety” or something similar are from second or subsequent generations (unless any have been vegetatively propagated from an original seedling) and therefore must be regarded as Gansu Mudan or members of the Gansu Group. As we have already indicated, we also include the originals here too. We hope we have proved conclusively that the use of the name Paeonia rockii is quite inappropriate for such plants and should not, therefore, be used in future.

Sir Frederick Stern (1884-1963) and the Highdown Plant

So at last we come to the man whose name runs like a thread throughout this story, Frederick Claude Stern, or just Fred as he was affectionately known to his many friends. There is not space here to do justice to his outstanding career except to say that when he died in 1967 his obituary in the Journal of the Royal Horticultural Society was headed “Col. Sir Frederick Claude Stern, O. B. E., M. C., F. L. S., V. M. H.”.

As a young man he spent some time big-game hunting in Africa and also rode as an amateur jockey in steeplechases. After he married in 1919 he and his wife, Sybil began creating a garden in an old disused chalk pit at Highdown in Sussex on a south-facing slope of the South Downs. They experimented with many kinds of plants to find out which would do well on a chalk soil and he wrote about their experiences in A Chalk Garden (1960), which is still well worth reading today. After her death, Lady Stern left the garden to Worthing Borough Council for the enjoyment of future generations of gardeners and many of the trees, shrubs, perennials and bulbs which she and Fred planted are still doing well nearly forty years later.

Stern wrote many articles on diverse genera, but he was particularly interested in Lilies, Iris, Peonies and Snowdrops. Today, he is chiefly remembered for his two best-known works, A Study of the Genus Paeonia, published in 1946 and Snowdrops and Snowflakes, published in 1956, both of which are now much sought-after collectors’ books. Peonies, in particular, proved to be very successful on chalk and many have survived up to the present day, including what is believed to be the original plant received from Cleveland Morgan (to be referred to henceforth as the Highdown plant), which grows near the western edge of the garden. It first flowered in 1938, less than two years after planting and specimens taken from it on May 10th that year are preserved in the Kew herbarium. Haw & Lauener (1990) refer to “two specimens grown from Rock’s seed cult. in the garden of F. C. Stern at Highdown” as if there were two plants involved, but this is clearly a mistake. Both of the herbarium specimens at Kew are from the same plant. By 1943 the plant was six feet high and “smothered with bloom” according to Stern, who submitted a vase to the RHS at Vincent Square on May 18th which was awarded with a First Class Certificate. Curiously, the record shows a second vase was shown on the same occasion by G. P. Baker of Sevenoaks, which was jointly awarded the FCC. Both were submitted under the name of P. suffruticosa. The only information on Baker’s entry form reads “It is said that it comes from Tibet”. Presumably, the two entries were at least very similar, if not identical, for the committee to make a joint award. A specimen taken from Baker’s plant, dated xx May 1940 is also present at Kew. G. P. Baker V. M. H. was a leading figure in horticultural circles at the time, a former President of the Alpine Garden Society and an expert on Iris. The latter interest alone would have linked him with Stern and there is plenty of correspondence between them on this, peonies and other, mostly bulbous subjects, in Stern’s file at Kew, but no mention of tree peonies. However, we think it can be no coincidence that Baker also attended the 1936 Rock Gardening Conference in London when Cleveland Morgan was present and was also at the same evening dinner mentioned before. Our guess is that both Stern and Baker were promised a plant at the same time and Baker would have received his later that autumn at the same time as Stern. The former’s old garden in Sevenoaks has long since been built on and the peony almost certainly no longer exists.

One important detail that we have not been able to resolve is whether the plants which Morgan sent to Stern and Baker were seedlings from the single plant raised by him or clonal material such as rooted cuttings, layers, divisions or even grafts. As ten years had elapsed since Morgan first received seed from the Arnold there would have been just enough time for his plant to have produced seedling offspring that would have been old enough to have flowered themselves by 1938. We know from the letter to Teuscher referred to earlier that seed was set and this seems to be the most likely source of the young plants Morgan sent to his friends. This would make the Highdown plant two generations removed from the seed collected by Rock, thus, in our view, eliminating the faintest possibility of its status as belonging to a wild species. In fact, there is ample morphological evidence to indicate the hybridity of the Highdown plant. Firstly, the filaments of the stamens are heavily flushed with a similar blackish-purple colour to that of the blotches at the base of the petals. All the contemporary Chinese descriptions we have seen of wild plants of P. rockii, including that in the Flora of China, give this feature as white or pale yellow and it can be no mere coincidence that that of all the other related species with which P. rockii is most likely to have crossed in the first place, such as P. ostii, P. spontanea (P. jishanensis) and P. qiui, is also described as being dark purplish-red. Secondly, we have observed in some blooms in some years a tendency for one to several extra narrow petals to be produced and this, too, can be regarded as a sure sign of the hybrid status of the Highdown plant.

Propagation and Distribution of the Highdown Plant

There seems to us little doubt that a high proportion of the plants grown in British gardens today as ‘Rock’s Variety’, ‘Joseph Rock’ or more recently and regrettably, Paeonia rockii, have descended directly or indirectly from the plant at Highdown, mostly by means of successive generations of seedlings. The first mention by Stern that he raised seedlings does not appear in print until he stated in A Chalk Garden (1960) “Seed of this plant has been raised and comes true.” By “true” he presumably meant that the resulting flowers were all basically white with dark blotches, not that they were all identical. It is also probable that he kept and sowed some of the seeds sent to him from Logan in 1938. In addition to the original, a number of plants still growing at Highdown today are clearly recognisable from foliage and flower as being related to the former and are almost certainly seedlings from it. Stern was known to be a generous gardener and would have given away his spare plants to friends and visitors. There are two different plants growing at Kew which the accession records show were donated by him, one in 1943 and the other in 1953. Neither are the same as the Highdown plant and both are obviously seedlings. In this way plants would have been spread around and no doubt successive generations of seedlings have been raised from them and further distributed. All will be different from one another whilst usually retaining the essential characteristics of a Rock’s peony, namely large, white or pink-flushed flowers of varying degrees of doubleness, with dark basal blotches differing in colour and shape. All should be referred to as belonging to Gansu Mudan or, more formally, as members of Paeonia Gansu Group.

The Highdown plant has also been propagated vegetatively by cuttings and by grafting. There is a note on Stern’s record card that two cuttings were rooted in 1956 and planted out in 1958. Neither of these appears to be present in the garden today. The late Graham Stuart Thomas grew a plant in his last garden at Briar Cottage, Kettlewell Close, Woking which he told one of us (C. S.) originated as a cutting from the Highdown plant and subsequent comparison has confirmed that the two were identical. We have no further information on any plants propagated by this means. Contrary to what is often written, it is not difficult to root cuttings, but it is certainly a slow business. (For further details see under Propagation p xx)

On the other hand there is a good deal of evidence that the Highdown plant has been increased by grafting, at least, in the UK. Notcutt’s Nursery of Woodbridge, Suffolk was probably the first to be involved. According to Frank Knight, a former Managing Director of the company and later a Director of the Royal Horticultural Society’s garden at Wisley from 1955-1969, in a letter published in the NCCPG Newsletter No. 5 for Autumn 1984, scions from the Highdown plant were grafted using the roots of herbaceous peonies as understocks in February 1951. The agreement was that the resulting plants were Col. Stern’s (as he then was) and in due course were despatched to recipients of his choice. How long this arrangement continued for is not clear but there is evidence that Notcutt’s continued to propagate the plant for their own customers in small numbers until at least the early 1960s. Knight mentions in his letter that seedlings of P. delavayi were also used as understocks, but that there were problems with suckering. It never found its way into the firm’s catalogues, however, and the demand always exceeded the supply. Ivan Dickings, a retired former head propagator for the company continues to graft a few plants from time to time and often uses P. delavayi seedlings as understocks.

There is an old specimen of Rock’s peony growing in the Dry Garden at the Savill Garden in Windsor Great Park and their records show that it was received as propagation material from Highdown in 1960. The following year plants were sent from Windsor back to Highdown and to Kew although as far as we know these do not exist at either garden today. Because of the short time-span we can assume that the plants must have been grafted even in the absence of any direct evidence. At the RHS Garden at Wisley, Surrey, there is a large plant growing in the wild garden which is recorded as having been received from Windsor in 1973, although there is apparently no corroborative record at Windsor. Scions from this plant were grafted onto herbaceous peony roots by Ivan Dickings in the mid 1990s and two plants were returned to Wisley in 1996 and are now growing well in the Hot Borders. All these plants have been examined in flower and have proved to be identical with the Highdown plant.

Probably the only person producing grafted plants of the Highdown clone commercially in the UK at the present time is Peter Catt of Liss Forest Nursery in Hampshire, albeit on a small scale. His stock plants originate from the Graham Stuart Thomas specimen referred to earlier. Rather unusually, Peter uses roots of P. delavayi as understocks, thus avoiding problems from suckering. A ten-year-old plant from this source is growing strongly in the Eccleshall, Staffordshire garden of one of us (CRS) and is currently two metres high and bore over thirty flowers in 2005.

Rock’s Peony in North America

We are indebted to Don Hollingsworth and Roy Klehm, both well-known peony growers from the USA for most of the information in this section. According to them most if not all the plants of Rock’s peony being propagated in North American nurseries at the present time are derived from scions imported from Highdown by the late David Reath of Reath’s Nursery, of Vulcan, Michigan. We have not so far been able to discover the exact date of the importation, but grafted plants were first offered for sale ( as P. suffruticosa var Rock’s) by Reath’s in 1971 so it was probably sometime in the mid-late1960s. In their catalogues at that time this was said to have proved to be the hardiest of all tree peonies with them, coping easily with winter temperatures down to minus 20 degrees Centigrade. An interesting and possibly significant statement by Reath appeared in a list of “Peonies for Hybridising” dated 1979 which included Rock’s peony. It was said to be “extremely fertile by selfing”. As mentioned earlier, there is a widely held belief in the UK that isolated plants do not produce seeds. Although we have occasionally heard reports to the contrary, it has always been impossible to prove conclusively that cross pollination could not have occurred somehow. Whilst accepting that Reath’s statement has no scientific standing, at least it throws some new light onto the question of whether isolated plants of Rock’s peony may be able to set seed occasionally in ideal conditions. It would certainly help to explain the relative lack of variation amongst seedlings in such instances and Stern’s claim that such seed breeds true.

Between 1969 and 1972 scions were supplied by Reath to the Klehm Nursery of Champaign, Illinois, who began selling plants grafted onto roots of herbaceous peonies around 1975 and are now the largest growers in the USA. Klehm at first listed the plant under the name of ‘Rock’s Variety’, later changing it to ‘Joseph Rock’ and then P. rockii (syn P. ‘Joseph Rock’). In their most recent retail catalogue (2005) it has reverted to just ‘Joseph Rock’. It would make a neat and satisfactory ending to this account if we could say that this form is identical to the Highdown plant but, unfortunately, this is far from certain at this time. Our personal experience is mostly limited to two young plants received from Roy Klehm that have not yet flowered, but the foliage appears to differ in some respects from the former, the leaflets being broader, thicker and lacking the characteristic bronze-red tinting in the early stages. We have also examined a plant growing in a Cotswold garden that was received from Klehm in the early 1980s. Although the flowers showed only minor differences in the size and shape of the blotches from the Highdown plant, the same foliar discrepancies described above were present. We are also puzzled by two close-up photographs of the flowers in Klehm’s current (2005) retail catalogue which look quite different, the one on the front cover closely resembling the Highdown plant but the other on page five seems to have much smoother and less indented petals. This latter form is very similar to a photograph which appeared in an article by Sir Peter Smithers in The Garden for November 1992 which the author described as “the plant distributed in the USA, propagated vegetatively….”. Although we are told that only one clone is involved, our suspicions that the original scions from Highdown may have been taken from more than one plant are increased by the knowledge that a second clone was discovered amongst the successful grafts received from Reath. This has many more petals and is marketed separately by Klehm as P. rockii Double or P. ‘Joseph Rock’- Double. We are not certain which, if any, of the plants growing at Highdown today could have been the parents of any of these USA clones, so the question of their precise identities must remain unresolved until we have had more time to study them.

A New Cultivar Name for the Highdown Plant

The last question to be resolved is what name should be applied to the Highdown plant? Having demonstrated its lack of entitlement to be included within P. rockii, the question of a cultivar name arises. Whilst accepting that there may be other similar individuals in cultivation, none, to our knowledge, has been (and still is being) vegetatively propagated on the same scale. In addition, its historical importance as outlined above cannot be denied and it is also the only survivor of the two plants that were jointly awarded an FCC in 1943. In our view, this is more than enough to justify a separate cultivar name to distinguish it clearly from all other clones. Both ‘Rock’s Variety’ and ‘Joseph Rock’ have been applied to it in the past by various authors, but none appear validly to have published either name with specific reference to the Highdown plant. As a result, these names have been used indiscriminately for anything that vaguely resembles a “Rock’s peony”, i.e. having large white flowers and dark basal blotches. Since the general acceptance of P. rockii as a species, this name seems to have taken precedence over both cultivar names, neither of which appear in the current edition of the Plant Finder, providing further evidence that they were probably not originally intended to represent a clone.

The earliest publication of the name ‘Rock’s Variety’ that we have found was in a note from Stern in the JRHS for August 1959. However, although it is clear that he was writing about the original plant, he did not describe it, merely stating that “it seemed to be exactly like the wild tree paeonies described by Reginald Farrer...”. In any case the word “Variety” contravenes Article 19.19 of the International Code of Nomenclature for Cultivated Plants (I.C.N.C.P.)(2004), thereby invalidating the name. Exactly when or who first coined the name ‘Joseph Rock’ is not clear but it has been in use at least since 1984 when an article by Diana Grenfell entitled Paeonia suffruticosa ‘Rock’s Variety’ appeared in the Spring Newsletter of the NCCPG. In it she used the former name interchangeably with the latter and further confused the issue by referring to several plants in other gardens as well as the Highdown plant without making it clear if she was treating them as a single clone or not. Cameron Carmichael, in the Spring 2001 issue of Plant Heritage, did his best to clarify matters by pointing out that “the only plant that should be called ‘Joseph Rock’ is the FCC plant.” However, the description accompanying the article is incomplete and there is no photograph or reference to an herbarium specimen, so we doubt if this constitutes proper establishment of the name under the I.C.N.C.P.. As already noted, the name ‘Joseph Rock’ is being used in the USA for at least one, if not two clones that appear to be distinct from the Highdown plant, adding yet another layer of confusion to an already chaotic situation. Even here, the catalogue descriptions we have seen are not precise enough to effectively establish the name.

In our view, the most satisfactory way out of this nomenclatural tangle as far as the Highdown plant is concerned, is to wipe the slate clean and start again with a new cultivar name. We propose that the most obvious and logical choice is Paeonia ‘Highdown’. This name is applicable only to the original plant at Highdown and its vegetative descendants.

Description of Paeonia ‘Highdown’

For a detailed botanical description we can do no better than point to Stern’s original description of P. suffruticosa published in A Study of the Genus Paeonia (1946) which was based on the two specimens held in the Kew herbarium taken from the Highdown plant in 1938. From a horticultural point of view there are several important features which, although not necessarily all confined to this clone alone, are nevertheless useful aids to its identification. Firstly, the young foliage in spring is more or less suffused with a reddish-bronze colour which gradually reduces as the season progresses, but is still present to some degree at flowering. (This may be reduced if the plant is growing in shade). Next, the colour of the reverses of the petals in the bud stage is pale lilac-pink and this shade shows briefly on the upper surfaces on opening, but quickly becomes pure white. Stern describes the petals as “numerous” but the actual number is 10 or 11, borne in two layers, those of the outer layer being slightly larger, roughly wedge-shaped and approximately 12 cm wide by 10 cm long. In addition, one to several extra strap-shaped petals is occasionally present. At the base of each main petal is an oval-shaped blotch, up to 4.5 cm long by 3 cm wide of a deep blackish-maroon colour, feathered lighter at the edges. The blotches show on the outer surfaces of the petals as a paler staining. One of the most important diagnostic features is the colour of the filaments of the stamens. There are about 300 borne in a dense mass on the central floral disc and the upper, most visible of them are heavily stained almost the same colour as the blotches, except for a short white base and a little more white at the top. The lower filaments are more or less white. The 5 green carpels with their creamy-white stigmas are partially enclosed by a cream-coloured sheath at first which splits open as they mature. Finally, mention must be made of the very pleasant scent which is reminiscent of roses. Once established, P. ‘Highdown’ will grow quite rapidly and is capable of forming a non-suckering shrub to about 2 m high and 1.5 m wide in ten years.


A number of kind people have helped us in various ways to unravel the tangled threads of the story of Rock’s peony. We would especially like to thank the following:

Céline Arseneault (Montreal BG), Chris Beardsley, Chris Brickell, Cameron Carmichael, Peter Catt, Anne Chambers, Veronica Cross, Lindsay D’Aoust, Tom La Dell, Ivan Dickings, Mark Flanagan, Karl Flinck, Maurice and Rosemary Foster, Chris Grey-Wilson, Don Hollingsworth, Reiner Jakubowski, Roy Klehm, Sybil Kreutzberger, Hermann Krupke, Alan Leslie, Ron Macbeath, Rolf Marquardt, Diana Miller, Elizabeth Morgan, Martin Page, Irmtraud Riek, Claudia Schroer (APS), Pam Schwerdt, Mike Sinnott and Barry Unwin. Also the staff at the RHS Lindley Library, the Arnold Arboretum, RBG Edinburgh, RBG Kew and the Bergius Botanical Garden.


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