Whilst readers of this blog may be happy to accept, without “proof”, that plants improve how you feel, many others remain sceptical. But there is actually a fair bit of sound scientific evidence to support the link between having plants around you and being less stressed and more productive. 
As long ago as 1998 Dr Tove Fjeld et al. published a paper “The Effect of Indoor Foliage Plants on Health and Discomfort Symptoms among Office Workers” which found, amongst other things, that complaints of coughs/sore throats and fatigue were reduced by 37% and 30%, respectively, in offices that contained plants.
Prof. Virginia Lohr, working at Washington State University, investigated the effect of plants on workers in windowless offices, and found plants improved productivity (12% quicker reaction time) and reduced stress (lower blood pressure), whilst participants reported feeling more attentive, too. (She’s also done some interesting work on how people respond to different tree shapes – I might write something about that in a later post.) 
There is now so much evidence for the beneficial effect of indoor plants that the Flower Council of Holland has established a program called Plants for People, and you can register for their e-newsletter here. (Lots of research papers and other info is downloadable from here.)
So, if you don’t have any plants to keep you company in your office during the coming winter months, then you’d better do somethig about it!
