Answer: Blueberries are blue, certainly not purple or yellow.

Many people hear that blueberries are purple, but this is where misinformation is getting the better of us. Of course, if you’re standing next to a berry bush and they turn purple as you watch them–sure–measure one’s blueness with another. Still, photosynthesis conversion converts so-called “red” pigments within plants to more common hues like yellow or orange/green hues with what we see as the human eye so red plants will often be interpreted by our brains as either orange/green or purplish due to any number of factors including sunlight spectrum conditions (ultraviolet radiation), the presence of other pigments within the plant itself, and so on.

A better question might be: what color are blueberries at one moment versus the next? Of course, none of us will sit around and watch mounds of them turn from green to purplish/blue to black; we’re likely aware that they’re green when picked, turn purple/blue during ripening, and eventually turn black once they’re ripe. So understanding what color our eyes see is perhaps the better question here.

The short answer: blueberries are bluish-green in their natural form (i.e., not yet picked or turned past green by sunlight).