In my garden borders , I like to plant things that compliment the other plants around them.

Such as this border at home, that I planted with Blue Perennial Geraniums, a Weigela bush that has Pink flowers in May/June and a Purple Lavender and the Green/Yellow shrub behind that brightens up the border.

A mixture of Yellows, Blues, and Pinks go very well together. In the containers are Yellow Margarites and Impatiens(Busy Lizzies) and Petunias. Again, all of the same shades against coloured Gravel , looks attractive in a Garden . Setting the plants to get their heights looking correct is Important too. So checking the Plant labels is vital to know their growing height.