Dive summary:

• It appears that two ways of going green in buildings – rooftop planting and rooftop solar panels – can have a symbiotic relationship.
• Research done in France found that solar-panel efficiency gets a boost on green roofs because plants cool the air and reduce dust and pollution, and both changes raise efficiency by 3% to as much as 16%.
• In Britain, a report says that using shade-tolerant plants that can flourish beneath the power panels do a better cooling job than some plants that have to have full sunshine.

From the article:

Plants reduce a roof’s contribution to the urban heat-island effect by lowering the surrounding air temperature through evaporation; this cooling can also make photovoltaic panels perform more efficiently. ...