How to keep a bucket of cut flowers going all week
A few flowers bought on the way home can last far longer than a single weekend if you treat the water and the stems right. Here is the short version of how florists do it.
Start with the stems, not the vase
Before anything touches water, cut about an inch off the bottom of each stem at an angle, using clean scissors or a knife rather than blunt household ones. A crushed or ragged cut seals over and stops the stem drinking. Strip off any leaves that would sit below the waterline, since leaves left underwater rot within a day and cloud the water fast.
Get the water right
Use a container that has been washed with a little soap and rinsed well, since bacteria left on the sides of a jug or bucket will shorten a bunch’s life more than almost anything else. Fill it with cool water, not warm, and add the little packet of flower food if the bunch came with one. It is mostly sugar and a mild acid, and it feeds the flowers while keeping the water slightly hostile to bacteria. No packet is fine too; a small pinch of sugar and a drop of household bleach do a rough version of the same job.
Keep the routine going
Move the flowers somewhere out of direct sun and away from a radiator or a stove, since heat is what pushes them to open and fade quickly. Change the water every two days, and recut the stems each time you do, taking another half inch off. This is the step most people skip, and it is the one that matters most, since the cut end heals over again within hours and needs freshening to keep taking up water.
A note on choosing them
At the shop, buds that are just starting to open tend to outlast ones already in full bloom, though this comes down to taste as much as anything, since some people want the full look right away. Either way, a bucket of flowers on a kitchen table or a bathroom shelf can hold its color for a week or more with only a few minutes of care every other day.