Every February 14th, a billion roses arrive almost simultaneously at doorsteps, petrol stations, and florist counters across the globe. Almost none of them bloomed naturally. The story of how they got there is a tale of refrigerated jets, chemical manipulation, and an industry that has essentially learned to cheat time.
By the second week of February, the farms of the Sabana de Bogotá — a high plateau nearly 9,000 feet above sea level in central Colombia — look less like agriculture and more like an industrial operation running at emergency capacity. Rows of polyethylene greenhouses stretch for miles, each one a precisely controlled microclimate where roses, carnations, and alstroemeria are coaxed into simultaneous bloom through a combination of artificial lighting, temperature manipulation, and a careful cocktail of chemical treatments. Workers move through the rows in shifts around the clock. Refrigerated trucks idle at loading bays. Somewhere overhead, a cargo jet is already en route.
Colombia alone supplies around 80 percent of the cut flowers sold in the United States for Valentine’s Day. The rest come from Ecuador, Kenya, the Netherlands, and a scattering of specialist growers across the globe. In total, the industry ships an estimated 250 million roses in the ten days before February 14th — a logistical and biochemical achievement that is, when you stop to think about it, remarkable. Roses don’t naturally bloom in February. Neither do many of the other flowers that appear on that date. Getting them to do so, reliably, by the millions, on schedule, is one of the most chemically sophisticated operations in modern agriculture.
Ethylene: The Enemy Within
To understand how the flower industry manages time, you first have to understand ethylene — a simple hydrocarbon gas that plants produce naturally, and that is both essential to and destructive of the cut flower trade.
Ethylene is a plant hormone. It triggers fruit ripening, causes leaves to yellow and drop, and — critically for florists — accelerates the aging and petal drop of cut flowers. Every flower produces it continuously, and flowers that are stressed (by heat, physical damage, or proximity to rotting fruit) produce more. In a commercial shipment of roses, a single damaged stem releasing ethylene can trigger a cascade of premature aging across an entire box.
The industry’s answer to this problem came in the 1990s with the development of 1-Methylcyclopropene, known as 1-MCP and marketed commercially as EthylBloc and SmartFresh. The compound works by binding irreversibly to the ethylene receptors on plant cells, blocking the gas’s effects. Flowers treated with 1-MCP in a sealed chamber before shipment can travel for days longer without showing signs of aging — their cellular machinery, in effect, cannot receive the signal to begin dying.
“It’s like putting the flower’s aging clock on pause,” says one post-harvest physiologist who consults for major Dutch exporters. “The treatment doesn’t stop the biological process entirely, but it buys you the time you need to get the product from farm to vase.”
1-MCP is now used routinely in the handling of almost every commercially traded cut flower. But blocking ethylene’s effects is only half the chemical puzzle. The other half involves getting the flowers to bloom in the first place — and on a precise schedule.
Gibberellins and the Art of Forcing a Bloom
In a greenhouse in Naivasha, Kenya — at an altitude that provides cool nights and intense equatorial sunshine — a horticulturalist is measuring out a foliar spray containing gibberellic acid, or GA3. It is November. The roses in this greenhouse need to be fully developed and cut in late January, giving them enough time to travel by truck to Nairobi, be auctioned through a Kenyan flower cooperative, packed into refrigerated containers, flown to Amsterdam’s Schiphol Airport — the world’s largest flower hub — and re-exported onward to retailers across Europe, all before February 14th.
Getting the timing right is an obsession. “You’re working backward from the date,” she explains. “You know how long a variety takes to go from bud initiation to a cuttable stem. You know your transit times. So you calculate the treatment date and you hit it. If you miss by a week, your Valentine’s Day flowers become Mother’s Day flowers.”
Gibberellins are naturally occurring plant hormones that promote cell elongation and, in many species, trigger or accelerate flowering. Applied as a spray or drench, GA3 can be used to push plants through their developmental stages faster than they would proceed under natural conditions. In some species, it can substitute for the cold period — called vernalisation — that plants normally require to transition from vegetative growth to flowering. Treat a chrysanthemum or a freesia with gibberellic acid at the right developmental moment, and you can compress its timeline significantly.
The timing of gibberellin treatment varies by species and even variety. Different rose cultivars — and there are thousands grown commercially — respond differently to the same treatment protocol. This means farms maintain detailed, proprietary records of how each variety behaves under specific chemical regimens, light levels, and temperatures. The knowledge is closely guarded competitive intelligence.
Light as a Chemical Signal: The Photoperiod Manipulation
Not all forcing is done with compounds in bottles. Many flowers are exquisitely sensitive to day length — a property called photoperiodism — and manipulating the photoperiod can be just as powerful as any chemical intervention.
Chrysanthemums are “short-day plants”: they only initiate flowering when the night is long enough. Under natural conditions in the Northern Hemisphere, they would bloom in autumn. To produce chrysanthemums year-round, and specifically to guarantee a Valentine’s Day peak, growers interrupt the dark period with artificial lighting — typically high-pressure sodium lamps or, increasingly, precisely calibrated LEDs — for a brief period in the middle of the night. This tricks the plant into perceiving an eternal summer. When growers want to trigger flowering, they simply stop the lighting interruption, allowing uninterrupted long nights to resume and the flowering response to begin.
The opposite approach is used for other plants. Carnations, the second most popular Valentine’s Day flower after roses, are day-neutral but respond to temperature. Dutch growers control carnation flowering by manipulating greenhouse temperatures across seasons, using heating and ventilation systems that are, in effect, chemical-free climate forcing operations.
In Ecuador — now the world’s second largest flower exporter, specialising in roses notable for their extraordinarily long stems — growers exploit the country’s unique geography. Situated on the equator at altitude, Ecuador experiences almost exactly twelve hours of daylight every day of the year, with remarkably stable temperatures. This makes chemical and artificial-light interventions less necessary for some varieties. But even here, post-harvest chemistry is intensive.
Cold Chain and the Chemistry of Preservation
Once cut, a flower enters a race against biochemistry. Respiration continues: the stem consumes carbohydrates, water moves unevenly through the vascular tissue, bacterial populations in the cut end begin to multiply and block water uptake. The florist’s familiar cut-stem-and-change-the-water ritual addresses this at a primitive level. Commercial post-harvest science does so at industrial scale.
Pulsing solutions — highly concentrated chemical solutions into which stems are placed immediately after cutting — are one of the industry’s primary tools. These typically contain a combination of a germicide (often a chlorine compound or silver-based biocide), a carbohydrate source to replenish the flower’s energy reserves, and often an acidifier to lower the pH of the water, which both inhibits bacterial growth and improves water uptake through the stem.
Silver thiosulphate (STS) is another widely used preservation treatment, particularly for ethylene-sensitive species like carnations and lisianthus. Like 1-MCP, it works by blocking ethylene receptors, but through a different chemical mechanism involving silver ions. STS fell out of favour in some markets due to environmental concerns — silver is toxic to aquatic organisms — and has been partially replaced by 1-MCP and by newer synthetic compounds like AVG (aminoethoxyvinylglycine), which inhibits ethylene synthesis rather than blocking its reception.
Vase life extenders — the small sachets of powder sold with supermarket bouquets — are a consumer-facing version of the same chemistry. They typically contain a biocide, a sugar, and an acidifier. Their chemistry is unsophisticated compared to what has already been applied at the farm and packinghouse level, but they do meaningfully extend vase life if used correctly.
The Refrigerated Sky Bridge
No amount of chemical treatment can compensate for poor temperature management in transit. Cut flowers are tropical products attempting to survive a global logistics network. They must be kept cold — typically between 2 and 5 degrees Celsius — from the moment they are cut to the moment they enter a warm shop or home. Any break in this cold chain accelerates both ethylene production and bacterial growth.
The Valentine’s Day surge demands extraordinary feats of refrigerated logistics. In the final two weeks before February 14th, flower cargo claims an outsized share of available belly-hold space on commercial flights between Bogotá, Quito, Nairobi, and Amsterdam. Dedicated freight carriers run additional services. At Schiphol, the Dutch cooperative auction houses FloraHolland processes flowers through refrigerated handling facilities that move millions of stems per day at this time of year. Temperature-monitoring sensors in individual boxes transmit data throughout the journey.
The irony is not lost on environmental critics that one of the most chemically and energetically intensive agricultural systems in the world exists to produce a product that will be discarded, usually within a week, to mark a single calendar date. The carbon footprint of a Kenyan rose flown to a British florist is estimated at roughly a third that of a Dutch greenhouse rose grown in the same country — the energy cost of heating a northern-latitude greenhouse through winter far exceeds the carbon cost of air freight from the equator. But the total environmental calculation, including chemical inputs, water use in water-stressed growing regions like the Sabana de Bogotá, and waste, is complex and contested.
What the Vase Doesn’t Tell You
The Valentine’s Day rose that sits in a glass vase on a dining table in Manchester or Minneapolis has, by the time it arrives, been treated with multiple synthetic compounds, kept at near-freezing temperatures for up to two weeks, flown across at least one ocean, and handled by dozens of pairs of hands across three or four countries. The chemicals that preserved it have largely done their work invisibly: the 1-MCP was gassed off in a sealed chamber; the pulsing solution drained away in a packinghouse; the silver compounds remained below detectable consumer thresholds.
What the vase also doesn’t tell you is that the same knowledge that makes Valentine’s Day flowers possible has genuine applications in food security and agricultural resilience. Post-harvest science developed for flowers has informed the handling of fruit and vegetables in food-insecure regions. Ethylene management techniques pioneered for carnations have helped reduce post-harvest losses of tomatoes and mangoes in developing markets. The chemistry of flowers, it turns out, is part of a much larger story about humanity’s relationship with plant biology.
But on the morning of February 14th, in the rush of unwrapping cellophane, none of this is on anyone’s mind. The roses smell faintly of cold storage and something floral that is hard to name. They are, against all biological logic, in bloom. That is, for now, enough.