You can use Dianthus 'Bath's Pink' as well as Scabiosa 'Butterfly Blue' + 'Pink Mist'
I also grow some lemon thyme and let it spill over the rocks that edge one of my borders. I also edge with daylilies, and plan to use some Verbena 'Homestead Purple' in the area where my mail box faces the street.

I used some hosta to define a smaller walkway area and it turned out real pretty until the voles started attacking. Plus the hosta grew bigger than I thought so this fall I am going to dig up one side and spread them out a little farther. Its really pretty in my shady area. I do have a new path in the variegated liriope and its turning out real pretty even though its used often and I still need quite a few more to finish the path. Take care, Judy