I agree with Verdun, the shrubs will fill the border eventually, laurels can grow very big and will need regular trimming. Is it a formal border, or will it be a hedge? If a border then annuals would be good to fill the space before the shrubs get big. Otherwise, as I have seen in Ireland along the hedgerows, you could plant hardy fuschias and crocosmia. If a formal bed with other plants the crocosmia may well takeover, but if it's to be a hedge boundary with a lawn that is mown it should be OK. It's hard to know without seeing it. Also we don't know where the sun is coming from.
at ford abbey I saw a border of Chinese anemones in pinks and whites which looked stunning ,also I love rudbeckia s .
If iut's wet, then could you go for some Astibes? Like others have said, won't be much room in a few years time with all those shrubs. Maybe you could get some ground covering plants, such as Geraniums, which will grow through things and cover the bare ground while the shrubs get established. Could also try some cheap seed growing annuals for quick cover. Cerinthe Major Shrimp is a great plant that will give some body for a period of time.