COLUMBIA, Mo. – Valentine’s Day flowers will last longer if kept watered and fed, said University of Missouri horticulturist David Trinklein.

Trinklein’s tips and homemade preservative recipe provide an extended warranty of sorts to make certain flowers last up to twice their normal lifespan.

Cut flowers age when they lose more water than they take up, Trinklein said. This most often happens when bacteria multiply and plug the water-conducting tissue of the flower known as xylem.

Too much sunlight, drafty areas and heat also can cause excessive water loss. The result is a flower that loses its attractiveness prematurely.

Improper care of flowers can be the kiss of death, so it is important to show them some love to avoid heartbreak.

First, if you receive boxed flowers such as roses, prepare them for arranging by cutting about 1 inch off the bottom of the stems. Otherwise, a bubble of air formed at the base of the xylem can slow the uptake of water. Make a slanted cut, which provides more surface area to take up water.

After cutting, immediately immerse the cut stems in a clean vase filled with water treated with a floral preservative. Cut the stems again about every third day and place flowers in fresh solution. This works equally well for flowers from a florist or from your home garden, Trinklein said.

When flowers arrive in a vase or if you buy a floral arrangement, ask the florist if preservatives were added. Boxed flowers such as roses may arrive with a small packet of preservative to add when the flowers are arranged.

Floral preservatives usually contain food, mostly in the form of sugar, along with a material to reduce the pH of the water, such as citric acid. The latter is helpful since bacteria tend to multiply more slowly in slightly acidic solutions. Additionally, preservatives contain a bactericide to further slow the growth of bacteria. Finally, a wetting agent is added to reduce the surface tension of the water. This allows the water to travel through the xylem more easily.

Commercial preservatives are convenient, but homemade solutions work equally well. Trinklein’s recipe uses lemon-lime soda to provide sugar and acid. Mouthwash provides bactericide and dishwashing liquid serves as a wetting agent.

David Trinklein's 'elixir of youth' for cut flowers

1 pint lemon-lime soda (not diet)

1 pint water

1 teaspoon antiseptic mouthwash such as Listerine or Scope

1-2 drops dishwashing liquid

Preservatives help flowers last longer, but they will not last forever.

“The beauty and ephemeral nature of a rose or other Valentine’s Day flower is part of what makes it special,” Trinklein said. “Perhaps they would not be as appreciated if they lasted forever.”