The Rose Valley is a notion, generally associated with the location where the Bulgarian oil-bearing rose grows. The Rose Valley is not a geographical name. It refers to the valley of the river Striama, west of the town of Misoura or eastward from the Koznitsa elevation towards the town of Kalofer. It is bordered by the Strazhata elevation.
The Striama Valley is often referred to as the Karlovo field. The valley of the river Toundzha, or the Kazanlak field, stretches westward of the town of Kalofer and eastward as far as the town of Tvarditsa. Unlike the Karlovo field, which is open to the South along the gorge of the river Striama and across the Sredna Gora Mountains, the Kazanlak field is not linked to Thrace. These two fields are referred to as the Rose Valley.
Researchers of the spreading of the oil-bearing rose have included in the notion of Rose Valley the southern slopes and fields of the central Sredna Gora mountains from Strelcha to the gorge of Striama. The southern slopes of the eastern Sredna Gora (also called Surnena Gora) have been included in the notion by others, together with the fields east of the river Striama and north of Chirpan to the Zmeevo pass near Stara Zagora.
The valley altitude is 710 m at Klisoura, 575 m at Rosino, 450 in at Sopot and 375 in south of Karlovo. The altitude of the Toundzha river valley is 600 m near Kalofer, 380 m near Kazanlak and in its eastern part it is 300 m.
The soils in the areas where the oil-bearing rose is grown are cinnamon forest and soils consisting of sand and loam and even fertile gravel and they allow easy cultivation. Of major importance is the fact that they do not retain water long after rainfall and do not get boggy, while they hold moisture in depth for a long time. The soils in the valleys of Striama and Toundzha have probably been formed with material from the Sredna Gora Mountains. The climate in the Rose Valley is transitional between moderately continental and transitional continental. The influence of the Black Sea is not felt because of the predominating western winds. The effect of the Aegean Sea is felt once in a couple of years from January to March. Sometimes, early warming may cause, "premature rousing" of the rose plants. The rose plants usually start coming into leaf around March 10 when the air temperature settles at over 5°C. The length of the spring warming determines the buds formation and is significant for the crops. Frosts are rare.
The rainfalls in the Rose Valley are heaviest in the spring, with a peak in June. Daily rainfalls are not abundant, yet the rainy days are many. This kind of weather prolongs the flowering period, suppresses oil evaporation, at the same time increasing the yield of oil and producing oil of good quality. A longer flowering period means a longer harvesting campaign at a lower daily output of flowering roses. Such conditions ensure good yield of oil.
The mean monthly precipitation in May and June is usually between 80 and 100 liters per square meter.
Cloudiness is of such a character that high air humidity is sustained. Daily temperatures are relatively high and the nights are cool. Dew is often formed and is welcomed by rose growers, as it is a sign of high yields of attar. The frequent rainfalls and cloudiness during the flowering period are among the main beneficial factors for obtaining larger quantities of essential oil and one of better quality.
The absence of intensive sunshine prevents undesired liberation of the volatile aromatic ingredients from the flowers. The wax film is thin, yet the plant does not strive to make it thicker to protect itself from strong solar radiation, as do roses in Iran and elsewhere. This explains the smaller content of stearoptene in the Bulgarian rose oil.
The western and northwestern winds, which are common during the flowering period, account for the movement of humid air currents towards the Rose Valley causing frequent rainfalls. The sudden violent, even stormy northern and northeastern winds, bringing cold air, are typical of the Rose Valley. It was believed that when these winds passed, spring was soon to come.
Every five to seven years there occurs a sudden warming during the harvesting time which hampers gathering, storing and distillation.
Old rose-growers were quite aware of these peculiarities of the climate, so they arranged all gyulpans, large and small, in such a way that they were opened to the East. The western and the eastern sides of the gyulpans were usually closed by stone walls.
To avoid the adverse effect of the winds on the rose bushes, they were always planted in hedgerows. The rows were oriented North-South or Northeast - Southwest. Thus arranged, only the first few rows were exposed to the wind, while the others protected each other. This rule was not observed only on sloped terrain, where the roses were planted along the horizontals to avoid erosion.
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