Flowers won't last forever, but they will last longer if you follow these tips.

Monday is Valentine’s Day, one of the two days (along with Mother’s Day) when flower sales are through the roof.

Some say flowers are a thing of the past in these days of social networking. Still, a gift of flowers can say more than a tweet of 140 characters or a picture of a bouquet of flowers you send to someone’s iPhone. Call me old-fashioned.

There’s something about the touch and aroma of flowers that can’t be sent through airwaves. You can’t breathe in the perfume of roses through your computer. The velvety petals stimulate the fingertips more than the flat screen of electronic devices.

Sure, flowers cost money. Everything does.

Sure, flowers don’t last forever, unless they’re artificial. But sending artificial flowers delivers a message we may not want conveyed: “second rate,” even though the flowers may last for years, gathering dust in a vase on the coffee table. If you’re thinking about the permanent botanical route, why not think about chocolates or diamonds instead?

Flowers eventually die. Just about everything does. It’s the circle of life. But the memories of fresh flowers remain. We know what roses and carnations smell like. We know how the petals of a daisy feel as we lament “she/he loves me, she/he loves me not.”

Roses are the traditional “I love you” flowers. In some cultures, the color of the roses means something. Few recipients are adept at interpreting the various meanings, so go with whatever colors suit you.

You can’t go wrong with red roses, though white and yellow are popular. Opt for newer colors, such as the terra cottas and bright oranges. There are even green roses, which seem more appropriate a month from now, but may be just different enough for that special person.

Carnations, lilies and tulips also make a statement, though the latter doesn’t have much aroma and are harder to make last in a vase. The tulip keeps elongating in the vase, so it tends to flop.

While some people are glad for any flowers, gladiolus really don’t say, “I love you” as much as they say, “With sympathy.” Avoid them unless someone is really into the spikes. If they are the only thing left, get a box of chocolate as well.

If you want to give the biggest bouquet of flowers for the least amount of money, give a daisy-like flower such as chrysanthemums or gerbera daisies.

It’s not that these flowers are usually cheaper than roses or carnations.

Botanically, every one of the so-called petals is an actual flower, and the center of the daisy-like flower is composed of hundreds of petal-less flowers. So that one mum flower is actually hundreds of flowers.

This means people should be careful when they ask for a bouquet of flowers. You might get one single chrysanthemum. On the other hand, the person who gives the one flower with, “Here’s a bouquet of flowers for you” might find the dog as a companion for the rest of the evening.

Tropical flowers, such as anthirriums, orchids and gingers, are also options. They tend to signify something more exotic and unusual, something atypical. Or, at least, that’s what you can say.

Keeping flowers alive through the coming week should be the goal. If flowers last longer than a week indoors, count yourself lucky. Some orchids may. Most roses won’t.

Two factors come into play more than anything else: the water in the vase, and air temperature.

The cooler you keep the flowers, the longer they last. Keep them away from furnace vents and fireplaces. We used to say to keep them away from the television, but the flat screens these days make it hard to balance a vase of roses on top.

The colder it is, the longer the flowers stay tight. The hotter it is, the faster the flowers open and fade away.

Keep flowers away from direct sunlight. They’ll open faster.

For something as easy as changing water regularly, it’s the toughest thing for flower lovers to do. It only takes a moment to dump the water out, rinse the vase with clean water and fill it up again. Yet few do it.

When you change the water, cut another half-inch off the stem ends. This allows the flower to absorb water more easily because cut ends eventually callus over, sealing the stem.

Avoid putting any leaves under water. They are simply bacteria breeding grounds, encouraging the water to turn murky with grayish-white things floating around. The water also starts smelling like an outhouse.

Use the floral preservative packets that come with most flowers. They limit bacterial growth in the water. Read and follow the directions on the package.

All this takes less than five minutes and may mean a few more days of enjoyment before you toss the flowers on the compost pile or in the garbage.

David Robson is a specialist with the University of Illinois Extension. For more gardening information, go to www.extension.uiuc.edu/mg.

State Journal-Register