The very attractive Himalayan Balsam (Impatiens glandulifer) plant was introduced into British gardens in 1839 and reminded people of the types of headgear that police wore so became known as Policeman’s Helmet.. Generally the flowers are dark pink although sometimes they are pale pink or white, with the plant growing about 2 metres tall but it can grow over 3 metres.  It can be found almost anywhere especially near water but unfortunately it has become extremely invasive and out of control in the UK with very little able to control it.   Seeds can be ejected up to 7 metres with an explosive force and carried by water to colonise further downstream but the main problem is that when the slightest piece of stem including a node is left on the ground it can quickly grow roots which makes it difficult to eradicate. In the area where these were plants were seen the area of Himalayan Balsam extended for many metres with many tall equally invasive Giant Hogweed flowers growing above it on a railway embankment.