If you have ever seen plants photographed using infrared film, you will know that they have a weird glowing quality when viewed at those wavelengths.
Apparently, the reason behind this has to do with quantum mechanics and photosynthesis. Photons with shorter wavelengths (violet and beyond) have higher energy than those with longer wavelengths (red and beyond, in the other direction). Since only photons with a certain level of energy can be used by photosystems I and II in chloroplasts, plants reflect insufficiently energetic photons, rather than absorbing them. This keeps them from taking in uselessly low energy photons which would simply turn into heat, rather than powering their photosynthetic machinery.