That are evergreen and flower in winter and summer.
Where are you located?
be cautious of the weight --- water + soil + pots can be deceptive, and if you are in rental property, be sure to check with your landlord ....
Depends on where you live. If in the U.S. you can contact your County Extension Agent and they'll provide you local information, so you're sure to succeed. Weight might be a problem as well as the continual dampness might eventually affect your roof. I'd be very cautious.
Really need to know to provide help;Where do you live? is the location(roof) sunny or shade, are you covering the actual roof or doing rooftop terrace type gardening,what is the surface of roof????? Golden Jasmine,Climbing Hydrangeas----really depends on how high the plants can grow too
House Leeks and Succulents.......
Bricks or Cemented, Totally sunny area
Temperature 48 - 50 Degree C
Need to green the roof planters qith ever green and flowering plants if possible mostly in a year require professional advice