JARS v53n2 - Danish Chapter: A Remote Island in the Realm of ARS Celebrating 25 Years

Danish Chapter: A Remote Island in the Realm of ARS Celebrating 25 Years
Bjarne Leth Nielsen
Alleroed, Denmark

Carl Adam Lehmann
Klampenborg, Denmark

Denmark is a diminutive country in the northern part of Europe. It is at the size of the state of Massachusetts and New Hampshire combined and hardly recognizable on a globe. How come that this country became a chapter of the ARS 25 years ago? At that time it probably was only the second chapter outside the USA.

The 20th of January 1974 twelve rhododendron enthusiasts - some of them members of the ARS - gathered in Copenhagen with the purpose of investigating the interests and possibilities of establishing a chapter of the ARS. All twelve favored the idea and an application was shortly after forwarded to the ARS. The application was approved unanimously by the ARS Board of Directors at their February meeting the same year. The ARS president, Alfred S. Martin, informed about the approval in a letter dated March 1st 1974. Since that time rhododendron growing within the framework of the new society has gained a continuous interest in Denmark, not least because of the international cooperation through ARS. The new society was named "Rhododendronforeningen - Danish Chapter of the ARS." Today 25 years later, the Danish Chapter is among the largest chapters within ARS.

25 Years Anniversary

The celebration of the society's 25 years anniversary will honor a period in Danish horticulture with a very strong growing interest in rhododendrons and where a large number of new species and hybrids came into culture. Danish Chapter has always been a very active society. It arranges approximately 10 member meetings per year, both in the Copenhagen area and in Jutland. Lectures are presented both by members of the society and by invited speakers. A quarterly bulletin "Rhodo News," each about 50 pages, with feature articles, debates, program reviews and factual plant information, is published as a supplement to the Journal of ARS. After all, not all Danes speak English. The society has established a display garden (ARS Journal 1/1985). The garden holds more than 1,000 species and hybrids. It is maintained by the members during annual activity days. Propagation is an important activity; many members propagate by sowing, by cuttings and by grafting. Controlled pollinations are favored, and seed lots are distributed not only to its own members but also to a high degree through the ARS Seed Exchange.

The Physiogeographic Conditions

What are the reasons for the successful expansion of rhododendron growing in Denmark? Of course the expanding society and its enthusiastic members must be acknowledged for this. Additionally we have to address the conditions imposed on us by Mother Nature - climate and soil.

The climate is temperate and the coastal position at the North Sea implies that humid air masses from the Atlantic traverses the country throughout the year. Average temperature in January and July is 32°F and 60°F respectively. The climate may be compared with the coastal regions in east Scotland. Extreme winters do occur when the Russian and northern Scandinavian high pressures block the incoming humid air. The temperature may then drop below 0°F, and the results may be fatal for a high proportion of the plants. If such cold periods take place in April at the onset of the growing season it may result in serious bark splits, eventually killing some of the plants. Many of the rhododendron addicts have chosen a positive attitude to the winter exterminations. Wonderful, now we finally got room for new and better plants, they say. Like in the US, we talk a lot about hardiness and many of us take the challenge and try to cultivate what is just below the local limits for successful growing. The result is obvious: The plant may recover partly during the following season but they look miserable. So my advise is: Do not try to grow what is deemed impossible, and if you do, remove the plant immediately when you have failed.

Danish ARS Chapter President and
Danish Chapter President Mr. Palle Kristensen and the
Danish Chapter Secretary/Editor ect. Mr. Jens Chr. Birck.
Photo by Carl Adam Lehmann

The Soil

The Danish soil is generally not ideal for rhododendron growing. The present day soil cover was formed 15,000 years ago during the glaciation of Scandinavia and Northern Europe. The soil (or the growing media as we like to say) ranges from a very clay rich glacial till in the eastern part of the country to sandy alluvial light soils, poor in nutrition, towards west. The tills are generally rich in lime as the shallow chalk deposits were eroded by glacial processes and the erosion products subsequently embedded in the soil. The western sandy soils are less alkaline but have a very low ability to withhold water. Conclusion: The Danish soil is definitely not ideal for rhododendron growing. The solution to this problem is peat moss. All rhododendrons in Denmark are grown in peat moss and we import huge quantities from mainly Sweden and Russia. The addition of peat moss to the garden may be just as expensive as the plants, and in the interest of economical survival we may mix the peat moss with up to 50 percent pine and spruce needles "recovered" from the local forests.

Danish Garden Traditions

The main difference between an American garden and a Danish garden is that in Denmark we fence our property with evergreen hedges - 6 feet high. We do not want people passing by to peep and take view on our little paradise. It is difficult to explain why, but it is probably part of a deeper mental heritage. Nonetheless we are always prepared to invite connoisseurs inside for coffee and a closer inspection. And we usually don't release them before we have turned every leaf and demonstrated the color and thickness of the indumentum. That process may easily last three to four hours.

At the beginning of the century the predominant garden architecture was the British style. We created miniature landscapes with crooked paths, a grove, a lake, an arbor and many trees. This was not a good idea, because the area was far too small for a "landscape," and the proportions became disharmonies after a few years. The garden tradition has since that time developed towards an architecture in harmony with the house and with the needs of the people living in the house. During the Second World War the land was cleared and everybody grew vegetables and fruit for the consumption of the family. The two extremes, the wild garden and the vegetable garden, slowly merged into a successful hybrid , a controlled horticultural area including a sunny terrace, a small lawn, a small area with strawberries and potatoes, small trees along the borders and regular beds for flowers, perennials and rhododendrons, with perhaps also a rock garden and a small pond. But we still hide behind the hedges. I prefer to say that I protect my tender rhododendrons against the cold easterly winds.

R. kiusianum var.
kiusianum in a terracotta pot
The white-flowered R. kiusianum var. kiusianu m in a terracotta pot.
Photo by Carl Adam Lehmann

It is as simple as that. We grow our rhododendrons and accompanying plants preferring acid soils at the suitable places in the garden. The big-leafed elepidotes are primarily grown in the shady areas, and small-leafed lepidotes are grown in the sun in the rock garden and near the terrace. Most of us mix species and hybrids as the overall visual impression is more important than the systematic and the collection of plants.

Those of us who are really hooked spend most our time out of office working in the garden. We work until darkness takes over, and often we make a final tour with wife or husband and a torch for a final enjoyable look at the work completed.

R. wardii hybrid named
'KH3', originating from Germany.
An R. wardii hybrid named 'KH3', originating from Germany.
Photo by Carl Adam Lehmann

From Hybrids to Species

What is preferable: healthy hybrids with lots of flower, perhaps of a leggy stature, or species with interesting leaves, a better stature but fewer and less impressive flowers. There is no simple answer to this, and for most of us it is fortunately not an either or. Species are interesting by the simple fact that they are limited in number and that similar plants may be found and identified in their natural habitat elsewhere on the globe. They may constitute wonderful ornaments in the garden year round. Hybrids have their peak season, May-June, when flowering wild. It is a challenge to hybridize and create new samples. There is a lot of synergy in hybridizing, two plus two equals five. We think that in Denmark we are somewhat more interested in species than you are in the United States. We generally don't name and register our hybrids, and when we make them most of us are too impatient and stop with the F1 generation. This means that the variation among the sons and daughters is limited, and selection of specific clones for further vegetative propagation is not expedient. We do dare a general statement: Within the Danish Chapter we like the hybrids, but we like the species slightly better.

Imports of Seeds and Plants

The establishment of the society 25 years ago as a chapter of the ARS implied strong international connections from the beginning. Of course these connections would only last with the help of active members writing letters and taking initiative in the exchange of seed and other plant materials. During the past period the members of the Danish Chapter have imported hundreds and hundreds of seed lots through the ARS seed exchange - and always seed of known origin, i.e., most often controlled pollination (CP). In that respect the education within the society has been successful, and almost exclusively seed of known heritage is sown. Also seed collected in the wild (CW) is popular, and there is a growing understanding of the fact that if we want to familiarize ourselves with the true species we need to replenish our genes continuously.

Many Danish members of ARS are also to be counted among the seed contributors to the ARS seed lists. We have even tried to inform contributors and the ARS seed director about the importance of mailing seed in bubble plastic in order to prevent crushing and milling of more than 50 percent of the seed grains in the printing machine. Unfortunately we have been less successful here, but the recommendation is herewith reiterated.

Rooted plants - almost exclusively species - have been imported in large quantities from the Rhododendron Species Foundation (RSF) and from British nurseries particularly from the Coxes in Glendoick. This is opposed to the general nurseries which import a large selection of hybrids from Dutch and German commercial propagators.

Last but not least a series of excellent rhododendrons have arrived in Denmark through personal contact. We have a good experience with cuttings being mailed simply in wet tissue paper and a plastic bag. A few days after shipment these cutting have been either grafted or embedded for rooting without having noticed their voyage of thousands of miles. Visitors and friends from overseas including among many others Warren Berg, Frank West, Bud Gehnrich, Gus Mehlquist, Ken Gambrill, Hideo Suzuki, Hans Hachmann, Kaarel Voitk. These rhododendron friends did always bring selected material of their favorites, and often they have had the pleasure of spotting their "own" plants when they revisited Denmark a few years later.

'Flava' x 'Jingle Bells'
'Flava' x 'Jingle Bells', a cross from 1978 with local
and American parentage; about 5 feet tall in 21 years.
In front is R. yakushimanum .
Photo by Carl Adam Lehmann

Traveling People Own Seed Collections

During the early stages of plant hunting in the Himalayas the Dane, Nathan Wallich, happened to be a co-player. In 1815 he became director of the Botanical Garden in Calcutta in India. From this base he was among the first botanists who traveled in the Himalayan range collecting seeds and plant material for research. It was probably Nathan Wallich who inspired Joseph Hooker to travel to Sikkim in 1848-1850. Hooker later acknowledged Wallich's support by naming one of his findings after him - Rhododendron wallichii . Wallich's influence on a broader botanical scale is reflected by the fact that the species name, wallichii , has been applied in more than 200 genera.

During the recent years a number of Danish rhododendron lovers have spent their money and their vacations in the Far East watching and describing the plants in their natural habitat and collecting seed. These travels, although carried out at a non-professional level, have triggered a strong interest in the discussion on classification of rhododendron, a subject which may still cause heated debates among our members. More important, however, is the flow of wild collected seeds into our nurseries and gardens - the optimum means of having the first generation "true" species still in cultivation. Nepal, Sikkim, Yunnan, Szechuan and Japan have been the favorite destinations for the recent plant hunting. A collection of rhododendrons, collected wild by Danes during the last 10 years, is presently being established in the Botanical Garden of Copenhagen in connection with the garden's 400 years anniversary in 2000.


Although Denmark is admittedly small, we ought to draw your attention to the island of Greenland, which is part of the Kingdom of Denmark. Being almost the size of Ontario and Quebec combined, it was from there the Vikings sailed to Vineland, today's Newfoundland, about 1,000 years ago. More interesting in the present context, however, is that Greenland hosts two rhododendron species, Rhododendron lapponicum and recently also R. groenlandicum (the former Ledum groenlandicum ). Unfortunately the former is extremely difficult in cultivation.

Predictions About the Future

The past has been fueled by a lot of enthusiasm and members wanting to learn and teach new members. We hope that this can continue, although the strain of being an "old established chapter" sometimes shows its face. Keeping in touch with other members of the ARS is an important part of the past and the future, visiting with you and having you visit us. Together we have a lot going for our common love of rhododendrons.