Those beautiful, long-stemmed roses your special guy just gave you for Valentine's Day will last a lot longer if you make sure to clip the ends at a slant before putting in water.
Remember to add an aspirin into that water as well to make those roses last longer.
Change your water often. Also, you should keep those stems clipped.
Another helpful way to preserve fresh flowers is to mix one quart of clean warm water, one tablespoon of bleach and one-fourth cup of lemon-lime soda.
However, if those long-stems have finally grown too short, you might try using a straw to insert the short stem in for maximum enjoyment!