Red Huckleberry (Vaccinium parvifolium) stems are typically green, however if a plant is growing in a place with lots of sun exposure, some stems (especially the outer ones) will get a fair amount of red in them. My understanding is the red comes from anthocyanins that help protect the plant from sunlight in excess of what it can otherwise tolerate without damage.
The photos featured here are of a particularly red plant that is growing just above the beach at the south end of Totem Park. I imagine the combination of direct and reflected sun is what has caused this plant to be pretty much entirely red-stemmed.
Now that I’m thinking about this a bit more, I find myself with questions I had not thought of before.
It had not occurred to me that huckleberry stems might photosynthesize, but now I wonder if they do (and perhaps do so throughout the leaf-less seasons).
I’m curious what season(s) drive the process. I can see arguments for and against winter/spring (leaves are off, but the light is less intense) or summer (light is more intense, but its attenuated by the leaves). Perhaps an experiment could be run by selectively covering stems seasonally and seeing how they respond.
How long would it take for the plant to respond? Will it gain/lose the red pigments within a season? Does it grow a certain color and persist that way regardless (this seems unlikely)?
I suppose it wouldn’t be too difficult to set up simple experiments to answer some of these questions, or perhaps I can find a natural setting that might offer some insight (a place where a plant is growing under alders, for example).
An older photo showing the typically green stems.