Studio method
Keeping cut flowers
People blame the flower. In the studio we blame the vase. Dirty water is a closed highway: bacteria colonise the cut, the stem stops drinking, the head droops, and no amount of sugar in a sachet will open that road again.
The method is short enough to remember and long enough that most households skip it. Empty the vase every morning. Wash it. Refill with clean water. Recut each stem on a long slant. Return the bouquet and move it away from sun, fruit and heat. That is the entire secret, repeated daily.
Flower food helps a little if the water is already clean. It does nothing if the vase has been sitting for three days.
A few stems need extra care
Woody branches — lilac, blossom, viburnum — need the bark scraped or the end split. Hollow stems such as dahlia hate an air lock; recut them under water if you can. Soft spring stems such as anemone and hellebore want a longer first drink in a quiet corner before they are arranged. Hydrangea that has gone papery can often be revived by a full submersion in cool water for twenty minutes. It looks like a rescue and it often is one.
If a single stem fails, take it out. One rotting end will spoil the rest. The bouquet should get lighter through the week, not sadder. That is also a kind of season: the arrangement changing as the days pass. We would rather you skip the packet and keep the ritual.
The shorter version of this note is the care studio. Use either. The flowers only care that you do it. If you want to know why we are so severe about Thursday buying, read What we buy on Thursday — vase life starts on the wholesale floor, not in your kitchen.