Have you ever made a jigsaw, only to annoyingly find several pieces missing ? I think this is a fair analogy when attempting to make a great border, as often they fall a little flat due to the absence of a plant or two.
I would love to be able to say my garden is perfect … (it is definitely not). However every year I come across previously “lost” pieces of my plant jigsaw.
I am particulalry enjoying Dahlia Black Beauty (Thompson and Morgan) and Dahlia Cactus Mix ( Sarah Raven) which were sown on the 7th March, and have been flowering since early August.
It continues to be an outstanding summer for perennials and annuals on my kitchen windowsill. 
In my garden – Heleniums with the purple foliage of Actea simplex Atropurpurea (in the background) and Sunflower Mars Midget are successfully filling many a gap.
However, these lost pieces are in a box of their own. The planting designs by Proffesor Nigel Dunnett, Tom Stuart Smith and Piet Oudulf at Trentham Gardens are truly fresh, inspirational and dynamic. Believe me you would find every missing piece you were looking for.
At some point I fully intend to make this jigsaw – lets just hope it is all there.. 
Sally Wicks 