The thick scent of lavender fills the sultry air in Bulgaria's central Rose Valley where the flowering rows lose their purple hue under the nimble hands of the lavender pickers.
It's the busiest time of year for local distillers, who industry experts say have dethroned France as the world's top lavender oil producer.
France itself now purchases between 80 and 90 percent of Bulgaria's lavender oil, with buyers including cosmetics firms as well as many distilleries who need it to make up for their own shortage, distiller Filip Lissicharov told AFP at the start of the picking season this week.
"What bigger recognition can we have for the top quality of our oil," he said.
France and Bulgaria together make up almost three-quarters of the world's lavender oil output, but France lost 50 percent of its crops between 2005 and 2010 due to a noxious bacteria, according to Crieppam, the French interprofessional centre for experimentation in fragrant, aromatic and medicinal plants.
Having won the lavender crown, Bulgarian producers "must now turn the focus to preserving this high quality, which will be key for keeping a hold on the market in the long run," said Lissicharov.
His family company, Enio Bonchev Production, is among the biggest lavender producers in Bulgaria, growing 100 hectares (247 acres) of certified organic lavender around the town of Kazanlak, at the foot of the Balkan mountains.
Plamen Stankovski of Bulattars, another major distiller in the same valley, also highlights the need to keep the traditional physical and chemical composition of Bulgarian lavender oil unchanged.
"Quality has started to suffer from a recent drive to achieve higher yields," he said, slamming the planting of non-traditional lavender types by some producers or the use of uncertified plant material.
"Still, we are doing great and can be proud, as the label 'Bulgarian lavender oil' has started to appear on cosmetics packaging as a quality standard."
In the fields, Lissicharov's 180 seasonal workers brave scorching midday heat to pluck the delicate blossoms when their concentration of oil is at its highest.
A good worker can pick some 200-300 kilogrammes (440-660 pounds) per day.
The lavender is then pressed by foot and distilled in the company's installations in the nearby village of Tarnichane, using approximately the same methods for producing Bulgaria's emblematic rose oil, also made there.
But unlike rose oil, which is used by high-end perfume makers and is 50-60 times more expensive, lavender oil is used in common cosmetics and can easily be lifted out of recipes if prices rise too high, distillers warn.
"Lavender oil is not a boutique product. It is used as an ingredient in soaps and shampoos and its price should be more reasonable, 50-60 euros ($61-74)," said Lissicharov.
Prices now are already "dangerously high", at 90-100 euros per kilogramme last year, up 15-30 euros from 10 years ago, he noted.
"We even had buyers offering as much as 105-110 euros per kilo," said Nikolay Nenkov of the Galen-N distillery, another large establishment in the region.
Some buyers have already started using cheaper lavandin oil -- a hybrid type of lavender with a larger yield but poorer quality -- and synthetic substitutes, according to apprehensive distillers.
Last year, France distilled about 25-30 tonnes of lavender oil, while Bulgaria's output was 45 tonnes, according to a market report by French group Elixens, a supplier of aromatic raw materials to the cosmetics industry.
Bulgarian distillers, however, put their production at 55-60 tonnes in 2011, double that of 2010.
The country's booming production is still a far cry from the communist-era years when it was a major supplier of all kinds of essential oils to the huge Soviet market, said Dimitar Kunov from the state essential oil testing laboratory.
Apart from France, the country now ships its lavender oil only to a handful of other countries: Germany, the United States, Switzerland, Australia and Japan.