This grower is sure of this plant identification.
Heads of tiny lavender-blue fragrant flowers that dry well Jul-Oct. 1-2m. Angular stems. Plant in drifts. Well-drained soil in full sun.
Purple top verbena, South American vervain, Tall verbena, Vervain
Verbena bonariensis (Purple top verbena). This is a tall perennial, which is grown as an annual, and produces deep purple flowers from mid summer to early autumn. The deeply toothed leaves cluster in a mounded rosette.
They are marginally frost hardy to frost tender. Grow them in medium, well-drained soil in full sun or at most partial-shade.
Walls, rock garden, attracts bees and butterflies.