Look to the Mediterranean for tall privacy plants that can take the heat. You did not mention your climate but in most parts of the US evergreen shrubs such as Italian Cypress or Skyrocket Juniper can handle the heat and give instant privacy but both will need large pots, good drainage and daily watering in hot weather. For low maintenance I suggest a screen of bamboo or privacy decorative metal in the back of a display and then arrange pots of sedums and succulents in front of the screen placed at different heights by setting their pots on top of stands or overturned pots. A screen takes up less room and needs no water. Large pots of ornamental grass have been used but grasses can look unsightly in the winter months. Bamboo in huge pots can look good all year but you will have watering to consider.  Tall flowering perennials such as Salvia 'Amistad' or tall dahlias my need to be staked and take most of the summer to become tall enough to provide privacy. A mix of evergreens, perennials and even flowering vines (think Black Eyed Susan vine) will give you a screening that will change with the seasons but only if you commit to daily care and careful watering. When you say low maintenance, I just keep coming back to screens. Keep growing, Marianne Binetti