JARS v47n4 - Pontic Azalea in Poland

Pontic Azalea in Poland
Tomasz Anisko
Horticulture Department
University of Georgia
Mieczyslaw Czekalski
Department of Ornamental Plants
Agricultural University Poznan, Poland

In Poland, undoubtedly, the Pontic azalea ( Rhododendron luteum Sweet = Rhododendron flavum G. Don = Azalea pontica L.) is one of the most rare native plants. The only natural stand of this species is located in Wola Zarczycka near Lezajsk, in the area of Sandomierski Forest, southeastern Poland. This stand was discovered by Mr. Jedrzejowski, a local school teacher, and reported by Professor Raciborski of the Jagiellonian University of Cracow in 1909 (9). Forty years later a natural preserve was established at that site in order to protect the stand of Pontic azaleas.

This discovery raised many controversies from the very beginning, because the stand in Wola Zarczycka was located over 200 miles west of the nearest continuous range of the species. The natural character of that stand was questioned. We have to keep in mind that instances of "beautification" of local flora with plants introduced from other parts of the same country were not uncommon in the past. Our grandparents had a slightly different concept of the preservation of nature than we have. There are several such places known in Poland where the Pontic azalea was intentionally introduced. One of them is near Ujazdow between Koluszki and Tomaszow Mazowiecki, central Poland. There are records confirming that Count Jan Ostrowski of Ujazd brought young plants of Pontic azalea from Volhynia (at that time part of Poland, presently Ukraine) and planted them in his forest in 1928. In 1865 it was a real sensation when a group of German botanists announced their discovery of Pontic azalea on the summit of Giewont in the Tatra Mountains. Soon it was explained that these shrubs were planted by Professor Nowicki, a botanist who could not resist the temptation of "beautifying" his beloved Tatra Mountains (11). It appears, however, that such an idea goes back well beyond the 19th century. A stand of Pontic azalea in the eastern Alps, near Pusamitz in Karnten, a region of Austria, discovered by Staber in 1934, has been proven later to be the result of an introduction from Roman times (13).

Drawing of R. luteum
The drawing of R. luteum is by Per Sigh, a member of the Danish
Chapter, a medical doctor, teacher and artist from Brabrand, Denmark.

Probably only as a legend can we consider the story of a Tartar khan who, according to unwritten "history," died in Wola Zarczycka during one of the escapades centuries ago. His comrades planted the burial mound with azalea shrubs brought from Volhynia or maybe even from the Black Sea region in order to remind their commander of his homeland. Supporters of this romantic story point out the unusually regular half-moon shape of the mound occupied by the Pontic azalea in Wola Zarczycka. Certainly this legend can inflame imagination and inspire poets. However, even if we come back to reality and agree that the stand of Pontic azalea in Wola Zarczycka is natural, there is still the question of how to explain its presence so far from any major range of this species.

The discussion of the origin of Rhododendron luteum was started by Rehman over a hundred years ago, in 1886 (12). The geographical range of the Pontic azalea includes three major centers and several isolated island locations.

Distribution of Pontic Azalea
Distribution of Pontic Azalea

The largest major part of the range is around the Black Sea, with the northern limits at Novorossiysk (Russia), eastern limits along the Great Caucasus and eastern Dagestan, southern limits along mountains of Pontus and northern Anatolia (Turkey), and reaching Bosfor and the Aegean Sea to the west (2, 13). In eastern Anatolia R. luteum is commonly seen but becomes less frequent further towards the west (2). Along the shore of the Aegean Sea it can be found in the Turkish provinces of Canakkale and Balikesir. The most western limit of the range reaches the Greek island Lesvos (2). In the Black Sea region R. luteum grows from sea level (as in province Rize in Anatolia) to altitudes of over 7,000 feet (in the Caucasus) (2). In the Caucasus R. luteum grows primarily on the slopes of northern and western exposures, with high rainfall. At altitudes between 2,000 to 5,000 feet it grows often as a dominating element of the understory vegetation in deciduous forests with Fagus orientalis , Carpinus betules , C. orientalis , Fraxinus excelsior , Tilia caucasica , Quercus petraea , sometimes mixed with Prunus laurocerasus . At the higher elevation, it grows in coniferous forests ( Pinus sylvestris , Abies nordmanniana , Picea orientalis ), often with Rhododendron caucasicum (9). In upper elevations, in open, exposed locations, the Pontic azalea creates dense thickets.

The second separated part of the range covers a smaller area in the Taurus Mountains in southeastern Turkey (13). The third major center is located northwest from the former ones and covers the northern portion of Volhynia (Ukraine) and southeastern portions of Polesye (Belorussia), an area of approximately 160 km 2 . The Pontic azalea grows there primarily in coniferous ( Pinus sylvestris ) and mixed forests, as well as in glades and around swamps. Its existence is threatened by intensive timber clearing. To answer the urgent need to protect the Pontic azalea and its habitat in Polesye the first two nature preserves were established there under Polish administration before World War II. There are several isolated stands of this species around the Volhynia and Polesye region, of which the most western one is located in Poland in Wola Zarczycka.

Two theories have been developed to explain the presence of R. luteum in Volhynia and Polesye. One of them hypothesized that this species remained there as a Tertiary relict. This theory has not received much support, since it seems unlikely that the Pontic azalea was able to survive the Ice Age in Polesye despite the moderating influence of the Slovechno-Ovruch Highland (along the border between Ukraine and Belorussia) (4). Paleobotanical studies also failed to confirm the presence of R. luteum in the Tertiary flora of this region (6).

The other theory suggests that the Pontic azalea immigrated to Volhynia and Polesye during the Quaternary Period. This concept raises the question: "Where did it immigrate from?" When Professor Szafer of the Jagiellonian University discovered fossil seeds of R. luteum near Czorsztyn in southern Poland, he formulated the hypothesis that in the Pliocene (the last epoch of the Tertiary) this species grew not only in the Caucasus but also in the Carpathian Mountains and the Alps, from where it became extinct during the Ice Age (Pleistocene) of the Quaternary Period (14). Kozyakov and Ivchenko proposed further that R. luteum had a continuous range covering the mountains of Southern and Central Europe (Alps, Balkans, Carpathians), Asia Minor and the Caucasus before the Ice Age (6). Isolated stands of Pontic azalea found west of the Sava River in Slovenia seem to confirm this theory. That area escaped glaciation and the Pontic azalea survived there as a Tertiary relict (13).

This finding creates a new dilemma: whether R. luteum appeared in Volhynia and Polesye as a result of migration from the south (Caucasus) or west (mountains of Central Europe). Several paleobotanists have favored the latter concept based on the fact that the distance of Volhynia from the Carpathian Mountains is less than from the Caucasus. Kozyakov and Ivchenko proposed that the migration took place in the Holocene (the most recent epoch of the Quaternary) (6). Professor Szafer suggested that it happened earlier at the end of the Pleistocene (14). One way or another, apparently, the Pontic azalea survived the Ice Age in the Carpathian Mountains, and then was forced by the competition of new vegetation to gradually migrate eastward through the Sandomierski Forest (11). Thus, the last stand of Pontic azalea in Wola Zarczycka would be living proof of the migration of this species which resulted in establishing a new isolated range in Volhynia and Polesye.

Location of Wola Zarczycka in Poland.
Location of Wola Zarczycka in Poland.

Wola Zarczycka, 50°18'N and 22°16'E, elevation of 600-650 feet, is located in southeastern Poland. The Pontic azalea resides there on top of the half-moon shaped mound remarkably raised above the surrounding area. The mound is around 120 feet long and 30 feet wide. Other woody plants growing on or around the mound are Pinus sylvestris , Prunus spinosa , Frangula alnus , Sorbus aucuparia , Quercus robur , Corylus avellana and Rubus sp. From the west it is surrounded by swampy woodland with Alnus glutinosa , from the east by xeric forest with Pinus sylvestris as dominating species. The Pontic azalea grows there in dense thickets which are almost impossible to pass through. They reach a height of 5 to 6 feet; however, there are numerous signs of pruning and breakage of branches. Despite the fact that the site is not easily accessible, it attracts many visitors in May when the Pontic azalea is flowering, and the visible damage is probably a consequence of this. Since the site is so tiny and the habitat so fragile, no more destruction could be tolerated and a fence has been built around it. However, the ability of the Pontic azalea to survive the damage to the above-ground parts is quite remarkable. A particular case is known, when in 1926 plants in Wola Zarczycka survived even a fire.

Soil in the preserve is extremely poor and dry. Nevertheless, plants grow there vigorously with a new growth reaching 10 inches, with no signs of injury by insects or diseases. Numerous spontaneous layers can be found around the plants despite the very dry conditions. Most probably the Pontic azalea thrives in this habitat thanks to its ability to reproduce vegetatively, since no self-seedings could be found at the time of our visit there. Intriguing is the fact that there is no expansion of Pontic azalea outside the sandy mound into the surrounding woodlands, even though the plants flower and produce seeds yearly.

The Pontic azalea is the only deciduous species of Rhododendron in Europe and western Asia. It was discovered for the western world by Tournefort on the east coast of the Black Sea in 1700. Tournefort included this new discovery in his "Corollarium Institutionum rei herbariae" (1703) where he named it Chamaerhododendros Pontica (15). In 1792, the Pontic azalea was introduced into the gardens of England, when Pallas brought it from the Caucasus. In 1812, seeds of R. luteum were listed for the first time in a catalogue of the Botanical Garden in Krzemieniec, which was at that time an important Polish cultural and scientific center (presently in Ukraine). Through the seed exchange program they were sent to Germany, France, England and Belgium. Not much later first hybrids resulted from crossing the Pontic azalea with several American species, later to become known as Ghent azaleas.

The Pontic azalea distinguishes itself by a great variation of shape and color of leaves as well as flowers. In 1927 Wolf published the results of his morphological studies on R. luteum conducted in the Botanical Garden and the Dendrological Garden of the Institute of Forestry in Leningrad (presently Sankt Petersburg). He characterized five varieties: glaucum , discolor , brevifolium , latifolium , and acuminatum , as well as nine forms: humile , excelsum , natum , pubescens , pilosum , glabrescens , calvescens , rarifolium , and vestitum (6). However, more recent studies have not supported those taxons (taxonomic units), and Wolf's varieties and forms are considered as so-called aberration, i.e., variation which cannot be related to any ecological or geographical factors (6). Nevertheless, this variation has a potential horticultural value, not all of which has been exploited yet.

Flowers of the Pontic azalea are extremely fragrant. If in great numbers they may even cause a slight headache on a hot day (6). In the past this plant, particularly flower buds, were used in traditional medicine. In Polesye, flowering twigs provided a panacea for poultry parasites (10). Dried leaves were sometimes used instead of tobacco and brewed leaves were successful in chasing away the devil forces (11). Instances of poisoning cattle which had grazed on the Pontic azalea were not uncommon in the past (10).

Rhododendron luteum is known for its adaptability and tolerance of unfavorable environmental conditions (2, 3, 4, 5). Being inspired by a brief story in an old newspaper about planting a number of Pontic azalea plants on the grounds of the metal mill in an industrial city of Stalowa Wola in southeastern Poland, not far from Wola Zarczycka, we decided to visit that place. What a surprise! After over 50 years since they were propagated from seeds brought from Polesye and planted, they are still there. There is no need to describe the pollution on the grounds of the metal mill to realize the hostility of that environment and thus to see a great potential use for this plant in a degraded urban condition. The observations in Stalowa Wola also confirmed the exceptional drought tolerance of the Pontic azalea. Our visit there was preceded by a period of several weeks of severe drought, which caused many other common shrubs including lilacs, forsythias, and privets to wilt. Surprise again! No signs of stress on the Pontic azalea. If someone would like to have a mysterious plant with fascinating ancient history to grace the garden with simple, not pretentious beauty, the Pontic azalea is certainly the choice.

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15. Millais, J. G. Rhododendrons and the Various Hybrids. Longmans, Green and Co. London, New York, Toronto, Bombay, Calcutta, Madras; 1924.