Sure... assuming that it's fairly fresh, cut about one half inch off of the stem (at a 45 degree angle) preferably under running warm water. But before you do that, rinse the vase with warm water and replace the water with one tablespoon of common table sugar dissolved in one teaspoon of lemon juice and one teaspoon of laundry bleach (chlorine). Mix this with enough warm water to fill the small vase and after cutting the rose as mentioned, place immediately in the vase. This all assumes the vase is a small vase holding about a pint or less of water. Should keep nicely for at least a week. Let it get a few hours of sun each day if you can...Good luck