I'm a career botanist and horticulturist. The CO2 as plant food meme is simplistic, inaccurate and has been beaten to death. Increases in atmospheric CO2 levels don't benefit  plants if they are stressed by heat or drought caused by global warming or are attempting to grow in soils saturated with salt from sea water rising into ground water. In short, many other factors influence plant health on local levels far more than increased CO2 in the atmosphere.