When somebody sends us a photograph of a bouquet that failed on day three, we ask them to do one thing before it goes in the bin: cut a stem in half lengthways and photograph the cut end. Nine times out of ten the bottom two centimetres are brown and dry inside while the rest of the stem is still green.
That is not heat damage. It is an embolism — an air bubble drawn up into the stem the moment it was cut in air, sitting in the xylem like a cork. Water cannot get past it. The flower is standing in a full vase and dying of thirst.
Cut it under water
A cut stem behaves like a drinking straw. Cut it in air and the negative pressure inside pulls a slug of air in behind the blade. Cut it with the end submerged and water follows the blade instead.
It sounds like folklore. It is the largest measurable difference we have found, and it is worth about three days.
Two centimetres off, at forty-five degrees, under running water. If you do nothing else on this page, do that. The angle matters less than people think, incidentally — it exists so the stem cannot sit flat on the bottom of the vase and seal itself against the glass. Any angle achieves that.
The second killer is bacteria
Vase water in a Paris flat reaches colony counts that would fail a swimming-pool inspection inside about forty hours. Bacteria block a stem from the outside as effectively as air blocks it from within.
This is what the sachet of flower food is for. It contains sugar, an acidifier and a mild biocide, and using half a sachet is worse than using none: you get the sugar, which feeds the bacteria, without enough biocide to keep them down. Use the whole packet in the water volume printed on it.
Then change the water every second day rather than topping it up, wash the vase with soap when you do, and take another centimetre off the stems. Two minutes. Three extra days.
Things that do not matter much
Aspirin, sugar, copper coins, a splash of vodka, lemonade. We have tried all of them against a control, unscientifically, for years. Nothing beat the sachet, and the vodka did measurable harm.
Room temperature matters less than people assume, as long as the flowers are not sitting directly under an air-conditioning vent, which dries petals from the outside. Afternoon sun through glass is a different matter and will cook anything.
Hydrangea is the exception worth knowing. It drinks through its head as well as its stem, so a floppy one can be brought back by submerging the whole flower in cool water for half an hour. It works twice, maybe three times, then the stem gives up.
If you have done all this and a bouquet from us still failed early, that is on us. Send one photograph within forty-eight hours and we remake or refund it.
