Hydrangea paniculata Little Lime ('Jane') (PBR) - It may be half the size of its sibling 'Limelight', but this fab new hydrangea still packs pretty good punch. It has strong stems that support the weight of the conical, lime green flowers, which fade to cream and then pink as the season progresses. Grate where space is limited, but you want a hard-working and colourful plant, it can also be grown in large pots if kept well watered.
Part of the garden design is to juxtapose circular and square/angular shapes. This flower support will be a nice contrast to the garden fence and has a pattern similar to the Fiesta Ware heart bowl valentine. There could be a series of an odd number of these supports to provide repetition. I would paint them Fiesta Ware orange, yellow, and purple for spot color.