Verbena officinalis, the common vervain or common verbena, is a perennial herb native to Europe. It grows up to a metre/yard high, with an upright habitus. The lobed leaves are toothed, the delicate spikes hold mauve flowers.
The Capensis large, elegant blue flowers are held well above the water at the tip of a sturdy green stalk. This plant blooms repeatedly from mid-spring to early fall.