Giant RhubarbInvasive Species IdentificationIn summer, giant rhubarb (Gunnera tinctoria) has huge leaves up to 1.5m wide. The leaves are lobed and hairy underneath.Prickly, reddish leaf stalks and flower heads grow from stems that can be 3.5m long.From April to October, flowers and fruits appear. Flower heads (3 – 4 per plant) are cone-like, long structures with thousands of small flowers. Small orange/red fruits contain the seed.Leaves and flowers die back from the beginning of October.ThreatGiant rhubarb forms large, dense stands along river banks, lakes, cliffs, roads and urban areas, blocking the sunlight from native species and badly affecting biodiversity.Giant rhubarb grows so thickly that it often obstructs access to recreational areas and its huge leaves can block drains and streams and increase the risk of flooding.When the plant dies back in winter, its decaying leaves give off a strong, rotting smell.ActionRemove any flower heads as early as possible as most seeds produced will germinate.Giant rhubarb can regrow from tiny fragments of over- or under-ground stems. Please consult a specialist before proceeding with a control program as incorrect action is likely to lead to spread.If you encounter giant rhubarb please enter the details into our log.