How about a lavender hedge ( Munstead is a nice compact one ) underplanted with hardy geraniums or bright orange and yellow nasturtiums

Less than a metre wide is very narrow - most shrubs will spread a minimum of a metre and many need 2 metres for width. If this border is next to a path, then you may not mind the plants spilling over onto it - if its onto lawn, it'll ruin the lawn. If it is onto lawn, I suggest you widen it if you want shrubs, or you'll be restricted to columnar growth types only.