Why cut flowers fade early, and what actually keeps them going

The clock starts at the cut

A cut stem is a plant that has lost its roots and does not know it yet. Everything after that moment — the water it can draw, the warmth around it, the bacteria multiplying in the vase — decides how long it keeps going. Across the flowers we work with most, the window runs from around 6 days to around 10, and nearly all of the distance between the short end and the long end is handling rather than luck.

The most useful thing to know is that most of that difference is decided in the first hour after the flowers arrive. Stems seal over as soon as they dry, a fresh cut reopens them, and water that has been standing in a warm room is already carrying the bacteria that will block them again.

What actually helps

None of this is a trick, and none of it needs an additive. The routine below is drawn from the care notes we hold for each of the 12 flowers in the catalogue, and it is the same handful of things a florist says across the counter.

• Take a finger's width off each stem at an angle before the flowers go anywhere near a vase
• Strip any leaves that would sit below the waterline, because a leaf left in water rots and feeds the bacteria that block the stem
• Change the water every two days rather than topping it up, and rinse the vase while you are there
• Keep the vase away from direct heat, off a sunny windowsill, and away from a bowl of ripening fruit

Different flowers, different habits

Vase life is a property of the flower at least as much as of the room. A rose gives about 7 days and a sunflower about 8. A lily reaches about 10, largely because its buds go on opening after the first ones have gone over, so the arrangement keeps changing rather than simply fading. A tulip gives about 6, and it is the one that most often disappoints people who were not expecting it — a tulip is not failing, it is just quick.

Each of them wants something slightly different. A tulip carries on growing after it has been cut, so it needs headroom in the vase and cold water, and it bends toward the light, which is why the vase is worth rotating each day. A lily will stain whatever its anthers touch, and it is genuinely dangerous to a cat. A sunflower drinks so heavily that the water wants topping up daily even between changes.

What the botanical names tell you

A florist's shorthand and a grower's shorthand are not quite the same thing. The rose you buy is a cultivar of Rosa, the lily of Lilium, the tulip of Tulipa, and the sunflower of Helianthus annuus. That matters more than it sounds, because the growing season, the vase life and the handling all follow the genus rather than the colour printed on the label.

When each is at its best

Seasonal stems are stronger, they last longer and they cost less than an out-of-season import, so the calendar is worth knowing before you order. In the northern hemisphere the tulip runs March to May, the rose May to September, the lily June to August, and the sunflower July to September. Outside those months the flowers are still available, but the stems are shorter and the price is higher.