Offices that boast greenery make employees happier and more productive, according to a new study.

The study found that adding plants to the workplace increases productivity by up to 15%, was conducted by comparing productivity levels in two large commercial offices in the UK and The Netherlands over a few months.

“Our research suggests that investing in landscaping the office with plants will pay off through an increase in office workers’ quality of life and productivity,” says Marlon Nieuwenhuis, lead researcher from Cardiff University’s School of Psychology.

“Our research questions this widespread conviction that less is more. Sometimes less is just less,” says co-author Professor Alex Haslam.