By regular and irregular, do you mean specular (i.e. mirror-like) and diffuse? If so, then the surface determines the type of reflection. Even though the frequency affects the angle of refraction (think: rainbows), it does not affect the angle of reflection.
If you think of light as a bundle of individual light rays all striking different parts of a surface at the same time, then each separate ray approaches the surface at a specific angle and bounces off the surface at the same angle in the opposite direction; angle of approach equals angle of reflection. If the surface is perfectly smooth--pretend it's possible--then every ray is reflected at the same angle and the light rays stay together as they reflect. But if the surface is not perfectly smooth, then each ray will strike the surface at a different angle, and all the individual rays will reflect off the surface at different angles and scatter. This is true regardless of the intensity or frequency of the light.