I'm working on a science-fiction worldbuilding setting and have been trying to find out what the survival benefits are of blue in plants, like this or this.

I have researched this but most of the answers that a Google search brings up are more to do with blue flowers, blue structural colouration in animals, and garden centre blogs and online stores selling conifers. The best I've been able to find has been a page about encouraging spruce plants to become as blue as possible by making sure they're fed planty of iron-rich fertilizer (but not fertilizing in the first year, so early impoverishment of nutrients seems to be a factor, but I don't see how that makes blue needles beneficial).

All I really want to know is what environmental conditions would cause a plant, any plant, to evolve blue leaves or needles.

Thank you in advance.

  • 1
    $\begingroup$ That's great, but I'm more interested in the time period long before Russia even existed. It's these plants' evolutionary bias towards being blue, and the pressures in their native environment that I'm interested in. $\endgroup$ Feb 26 at 13:46
  • $\begingroup$ I’m voting to close this question because this question belongs on the worldbuilding stack. $\endgroup$
    – John
    Feb 28 at 14:20

According to at least one gardening tutorial I found, the blue color of the Colorado Blue Spruce is not actually related to the color of the pigments in the leaves.

"...the intensity of the blue of a Colorado blue spruce (selections of Picea pungens ‘Glauca’) depends on the concentration of its “bloom,” a powdery white wax that coats its needles."

I can't say if this is the case for all "blue" conifers, but given that this tree is especially tolerant of cold and drought, it seems likely that the waxy "bloom" is related to retention of water vapor and possibly exclusion of external water from the needles. Since there are lots of other plants with waxy coatings that don't have such a powdery blue appearance, I'd speculate that it may also contribute some protection from UV radiation for these high-altitude trees.


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