Talbaghia violacea ~ hardy, long flowering, easy to grow, low maintenance. 'Dark Star' variety shown. Also available in pure white 'Milky Way' variety. Good for edging/borders. Keeps bugs down - is an Allium after all.
Borders don't have to be large or complex to have visual impact; just four or five well-chosen plants can work wonders. Here, a border of purple African daisies, lobelia, sea lavender and silvery dusty Miller hugs a pool.