Britons spend more than £1.5bn a year on cut flowers, and Kenya has nearly a quarter of the market, which peaked as millions of Britons gave flowers to loved ones on Valentine's Day. As many as 50,000 people now work in Kenya's flower industry, and for the past few weeks they have been working flat out to meet orders.
The industry, now the country's second-largest exporter, is driving the expansion of Kenya's economy and is fuelling a population boom around the shores of Lake Naivasha. But the British love of roses and saying it with blooms has led to a tense trade-off between economic progress, environmental destruction and social problems.
At the Oserian farm, where 5,000 workers labour in a sprawl of greenhouses from where daily shipments head straight to Tesco's, Sainsbury, Marks & Spencer and other outlets, the Fairtrade brand is seen as a way to polish the industry's tarnished image and balance the competing interests of business and Lake Naivasha's ecosystem.
For years, human rights groups lambasted Kenya's mainly foreign-owned flower companies over low pay, chemical hazards, and the plight of casual workers.
Conditions have mostly improved since then and the ethical imperative has also prompted the company to reduce its environmental impact, employing hydroponic farming to cut back on water use and getting three-quarters of its energy from a geothermal spring