Himalayan balsam is not native to the UK, and was introduced from the western Himalayas in 1839 as a garden ornamental. It has since escaped and spread across the UK. Himalayan balsam is an annual plant, growing in dense stands up to 3m in height. It has hollow, jointed pinkish-red stems which are sappy and brittle. The leaves are shiny, dark green and spear-shaped with a dark red midrib, up to 150mm long. The flowers are fragrant, normally purplish-pink; but can sometimes be white, they are slipper shaped and held on long stalks.