Deck tree - This golden maple makes a beautiful potted tree in this tall terra cotta. Maybe a Princeton Gold Maple "Acer platanoides" or a Golden Full Moon Maple "Acer shirasawanum 'Aureum'" (small, shade)
Hydrangea paniculata Limelight, large white blooms tinged with pale green; trailing Ivy at the base spills over the sides of the classy zinc planter boxes. Baltic Ivy (variegated creamy edge) would combine well too.
Potted boxwoods offer formal elegance with little maintenance. This large American variety creates a living wall in a line of concrete planters. Plant Boxwoods in Pots I could use to disguise septic tank