Lately I've hit a red streak, I can't tell you how it happened, but I've found myself having more and more red photos. In some comments I received people kept telling me how difficult it is to capture the color red.
What works best for me is natural light, but not too sunny, because the sun will add warmth to the red and give it a slight orange hue. A blue/white fluorescent light will turn it lightly purple. The best choice is natural light coming from a nearby window, but not direct sunlight. If you want to work indoors with flowers, using artificial light, you may change the white balance of your camera, or invest in a light bulb re-creating natural light. Those you can find at Lowes or Home Depot, they are used for indoor plants, but they work fine for photography too!