It's easy to make real flowers glow under black light or even in the dark. Here is a collection of glowing flower recipes.
Flower Science Experiment for Kids: DIY Glowing Flowers
Scientists create glow-in-the-dark plants
How to Make a Glowing Flower
DIY Glow-in-the-Dark Flowers
Glow Rose Wallpapers - Top Free Glow Rose Backgrounds - WallpaperAccess
How to Make Glow in the Dark Flowers - Jennie Masterson
How To Make Glowing Flowers (for pennies apiece)
Make Flowers Glow In The Dark (with highlighter fluid and UV light)
How to Make Glowing Bubbles
Glowing Paper Flowers : 10 Steps - Instructables
DIY Glow-in-the-Dark Flowers
Pictures: Flowers Glow Under UV-Induced Visible Fluorescence