A little later on, melampodium will add great billows of yellow and even later than that Salvia leucantha will add bigger billows of a lighter purple. Right now, everything is mostly green and purple.
Purple Datura even has dark stems. The fully open blossoms have swirls of white, the buds are darkest purple. The blooms are fragrant at night, attracting moths whose larvae are already starting to eat the leaves.
The leaves of crinums and Bengal Tiger cannas make a foil for darkest 'Black Magic' elephant ears and Persian Shield.
Purple Heart and Bulbine -- tangerine Bulbine blossoms don't show up well, no matter how hard I try.