Mid Summer Combo

As I anxiously await Spring I find myself pouring over Garden Magazines and searching the internet for the perfect plants to plant in my garden next Spring. One of the combos I've decided on is Agastache 'Golden Jubilee' (Anise Hysop) amd Echinacea 'All that Jazz' PPAF (Coneflower). Both of the plants are mid summer to early fall bloomers, but 'Golden Jubilee's beautiful golden foliage will add color to my garden all season long. I think 'All that Jazz' unique fluted petals are so cool. This plant is a must-have in my garden! Is such a heavy bloomer that if I can snip a few flowers off and put them in a vase and you won't even notice. Both plants are very fragrant, which may bother my allergies, but I don't care, I love having scents in my garden!
Since the Agastache is 18-24 in tall I would put it in front of the Echinacea, which is 30-46 inch tall. Now I just have to figure out what to plant in front of the Agastache! Maybe a Dianthus??