This purple Veronica 'Eveline' in the Southwest Garden: Section C. (SWGC#29)

"A hybrid Speedwell from the Netherlands that shows great promise. This forms a bushy, upright clump of shiny dark-green leaves, bearing upright wands of deep magenta-purple flowers for weeks on end, beginning in midsummer." -http://www.perennials.com/plants/veronica-longifolia-eveline.html