Himalayan Balsam Frequently Asked Question

What is Himalayan balsam?

Himalayan balsam (Impatiens glandulifera) is an annual plant native to the Himalayas. Also know as Policeman’s Helmet, Bobby Tops and Gnome’s Hat Stand due to the unusual shape of its petals, Himalayan balsam can be found throughout the UK where it is classed as an invasive species. Originally introduced to the UK by Victorian horticulturists in the 1830s, Himalayan balsam quickly spread throughout the nation’s network of watercourses and can be found growing on riverbanks and rural areas to this day.

What does Himalayan balsam look like?

The most striking characteristics of Himalayan balsam are the pink/purple hooded petals and the strong balsam scent, attracting numerous insects such as bees and butterflies. The hollow stem of the plant appears reddish-translucent and reaches heights of 2-3m when fully developed. The serrated, pointed leaves of Himalayan balsam are green in colour and grow 5-18cm long, growing from nodes in the stem in pairs or groups of three. Adult plants produce a number of delicate diamond shaped seed pods that disperse their contents by “exploding” on physical contact, curling back each of the five sections of the pod projecting seeds up to 7 metres.

Why is Himalayan balsam a problem?

An adult Himalayan balsam plant can produce up to 800 seeds enabling a small colony to rapidly spread, especially along riverbanks where it is commonly found. Buoyant seeds can be carried downstream to colonise far from the parent plant and are even capable of germinating underwater. Growing in dense clusters Himalayan balsam is able to prevent local native plant species from developing by starving them of sunlight and minerals.

What damage can Himalayan balsam cause?

During the latter months of the year Himalayan balsam can leave entire stretches of riverbank bare as it dies off, leaving the area more susceptible to erosion.

How can you kill Himalayan balsam?

Eradication of Himalayan balsam can be conducted in the following ways:

Chemical- The application of herbicides is a very effective control measure for Himalayan balsam. The specific herbicide used and the timescale needed to achieve eradication will depend on factors such as the infestations proximity to watercourses and the local wildlife.

Hand pulling/Digging- Himalayan balsam is a shallow rooted plant that can easily be pulled up in its entirety by hand. Extreme care must be used when handling seed baring plants as even slight contact can result in the dispersal of the seeds.

Grazing- Cattle and sheep can graze on Himalayan balsam which can help to reduce new growth but is unlikely to result in complete eradication.

How can I prevent Himalayan balsam spread?

Himalayan balsam’s unusual method of seed dispersal is both effective and difficult to prevent, especially in an area of frequent human or animal traffic. As direct contact with the seed pods is required to successfully disperse the numerous seeds, isolation of Himalayan balsam is necessary to reduce the chances of reproduction. Any new growth that is discovered should be addressed using one or a combination of the control methods listed above. Small infestations can be dealt with quickly by pulling up any growth by hand whereas well established colonies of Himalayan balsam should be controlled by trained and experienced personnel.

Can I plant Himalayan balsam?

Under the Wildlife and Countryside Act 1981 it is an offence to introduce Himalayan balsam into the wild.