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.
It is really thirsty, water freely during growing months and moderately in Winter. Keep soil evenly moist, but do not overwater making the soil too soggy.