Most shade cloth is black. But there is also green. Red. Grey. White. Silver.
And we might wonder, there a difference, other than looks?
A few experiments have shown that shade cloth color can influence plant growth.
One experiment showed an increase in internode length and leaf width in blueberries grown under black shadecloth. The other shade cloth colors in the study—gray, red, and white—did not increase growth.
Another experiment used tea plants as subjects, finding black, blue, and red shade nets increased the height and stem diameter, net photosynthetic rate, and reduced cold damage in winter. No significant difference was found among the black, blue, and red shade nets on growth.
A third found chili plants to have greater growth under green and black shade cloths, but not white.
Tea plants, Camellia sinensis, growing under shade cloth
Should those of us growing bonsai change the shade cloth color we already have? Maybe not yet. It does appear plants have different responses to the color of shade cloth, but this field of study is just beginning.
This might be something for bonsai artists to keep an eye on, if the color of our shade cloth can help keep short internodes, for instance. Or to help build more biomass, if we have a young, developing bonsai collection. The chili pepper experiment suggests that white shade cloth might be an option for keeping small leaves and shoots, but that is with a pepper, not a maple or an azalea. Otherwise, in general, black shade cloth appears a good option to encourage plant growth.
Highbush Blueberry
The original articles:
Blueberry experiment: https://www.researchgate.net/publication/257821038_Colored_shading_nets_increase_yields_and_profitability_of_highbush_blueberries
Camelia japonica experiment: DOI: 10.3389/fnut.2022.786421
Chili pepper experiment: DOI: https://doi.org/10.21273/HORTTECH04895-21