Posted: 15/03/2016 at 10:17
I hope they aren't Leylandii that you have in there already. They grow enormous.
Look up hardy perennials on Google if you want flowers that come up every year, but I think front garden beds like that look quite nice with shrubs in them, tallest in the middle and shorter round the edges. Look up Choisya, Weigela, Caryopteris, Sambucca Black Lace (will need yearly pruning), small leaved lilac etc.