Never..

• .. break, crush or split the stems! This encourages bacteria to grow, which stops the flowers drinking the water and absorbing the nutrients they need.
• .. put Daffodils in mixed arrangements. Daffs release a latex slime that harms other flowers. Use the specialist bulb cut flower food to counteract this.
• .. put flowers near fruit and vegetables, or mix (nearly) dying flowers with fresh ones. Older flowers, fruit and vegetables all release ethylene gas which prematurely ages fresh flowers.
• .. put coins, lemonade, sugar, aspirin or bleach in the water. They waste your money, don’t do your flowers any good and may shorten their life considerably.

A few tips for displaying your flowers
How to make your flowers last longer
How to make your flower arrangements last longer