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.
They grow well in a standard peat moss/sand which can be anything from 50% to 70% peat moss. There's no need to fertilize, as the plant relies on insects for food.