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 fruits are a conical pod with seeds contained in holes in the pod. When the seeds are ripe, they become loose in the pod. The pod then tips down towards the water, releasing the seeds.
It grows-up to a height of 4-6 feet depending on the dept of the swamp or creek it is growing in, maximum spread of 9 inches. It can be grown in a pot. Widely cultivated for its large pink flowers.