There are a limited number of colors that a bee can see. Bees do use sight to find flowers but they are looking for pollen to feed to their offspring and there are a variety of other characteristics in a flower that cue its readiness and benefit their ability to collect its pollen. They prefer flowers that have visual cues, like colored pathways, that guide them towards the center of the flower, a fresh scent indicating waiting pollen and a flat landing area on the petals. Some of these characteristics may be apparent to the bees but not to humans, like pathways visible only in ultraviolet light and small changes in scent and pollen presence. Limiting colors present in a garden does not mean that you will eliminate bees.

As to the colors that a bee can perceive, Bee Culture, the magazine of American beekeeping, provides the following explanation.

"Like us, bees are trichromatic. That means they have three photoreceptors within the eye and base their color combinations on those three colors. Humans base their color combinations on red, blue and green, while bees base their colors on ultraviolet light, blue and green. This is the reason that bees can’t see the color red. They don’t have a photoreceptor for it. They can, however, see reddish wavelengths, such as yellow and orange. They can also see blue-green, blue, violet, and “bee’s purple.” Bee’s purple is a combination of yellow and ultraviolet light. That’s why humans can’t see it."