I live in the Pacific NW where we have a lot of cloudy days, even in summer, and temperatures rarely get into the 80's. I'm growing probably 80-90 bamboo species, mostly runners, but maybe 15 or so clumpers. Because of the mildness of the winters and the species I choose to grow, I typically don't get culm dieback, or even much leaf loss over the winter, so most of my bamboo keep all their culms until the individual culms die a natural death after many years. One thing I have noticed is that many of my green bamboo do not stay green over the years, but change to a yellowish or yellowish-olive color over several years. New culms come up dark green, but change over time. Most of my bamboo sit out in the open with little or no shielding by trees from the sun we do get. It also seems that some bamboo with particularly dense foliage will not have as much color change with the inner culms that are shielded, so I've always assumed that the color change is due to sun exposure over time. However, I'm curious to see what others have experienced and whether this color change can be prevented or affected by attention to fertilizer or soil pH.

Observations, insights, ideas?

Hello Gil,

I think you are correct regarding sun exposure and color change. Empirically it seems that the culms exposed to the most sun turn soonest, and those it the interior of the grove turn later or not at all. Every green bamboo that I have observed will eventually turn yellow, or their mature color of black, gray, brown with spots, etc., when exposed to sunlight.

There are likely/are other factors contributing to color change such as perhaps absorbed minerals, genetics, and others, but I have observed the effects of sun, and can't easily observe the others.

Best regards,

David

This may be the most pure black culm we have ever seen. Found on P. nigra 'Ebony' growing at Shweeash Bamboo. Interestingly, it is hidden in almost full shade.


from http://www.shweeashbamboo.com/Phyllostachys%20nigra.htm

Also check this out.

viewtopic.php?f=4&t=4388

Very interesting what Fox says about moisture. Shweeash is closer to the ocean than most bamboo farms. I have been misting my nigra and it seems to bear out. A sample of one is not exactly proof. It is also not clear that nigra turns black from a similar mechanism that makes green bamboo fades. Just some other interesting discussions on this topic.

I would love to know what really makes nigra turn black faster.