I have been making forays into the fields nearby to take photographs and it seems to me that there are more yellow flowers than any other colour. If this is simply a good colour to attract pollinators, why wouldn't they all be yellow? Or is colour what dictates which type of insect will visit a given plant? For example, is a bee required to pollinate one flower and a wasp or butterfly another?
Different colours attract different pollinators, and perhaps also work better in different habitats. Most insects go for various whites and yellows, while red usually indicates bird-pollinated. Around here, white is the commonest, well ahead of yellow, in shade-tolerant woodland flowers, while yellow is perhaps commoner in meadows. An additional complication is that insects and birds can also see ultraviolet as a distinct colour; we can't see it at all. Many flowers have ultraviolet-coloured parts which to us are only detectable by special photography.
There might be trends. Seems a lot of trees in our area have white flowers, like hawthorn or Pacific dogwood. Berries seem predominantly dark. Flowers - seems on where it's at. A field may have a lot of white Queen Anne's lace. Other areas yellow dandelion. Oregon grape is not a "wildflower" as in a small one, but that's yellow. The most variety I see is in north California. Blue, white, yellow and orange. But I saw a ton of blue flowers several weeks back driving back and forth from north to south Oregon moving out stuff up. Blue was by far the most color I saw. Bear's breach near the coast is out now and it's white.
I've long noticed a trend for deciduous trees/shrubs to have red berries (e.g. Rowan, Hawthorn), and evergreen trees/shrubs to have purple/black berries (e.g. Ivy, Bay Laurel). Quite a few exceptions (e.g. Amelanchier deciduous with purple berries, Ilex aquifolium evergreen with red berries), but also several genera to which it does apply even when the genus contains both deciduous and evergreen species (e.g. Berberis vulgaris, Daphne mezereum, Viburnum opulus deciduous, red berries; Berberis darwinii, Daphne laureola, Viburnum davidii evergreen, purple berries).
