What is himalayan balsam?

Himalayan balsam thrives in damp soil and is found alongside waterways, in marshes, and damp woodland edges. Plants can grow to a height of up to 2.5m. Leaves are lance-shaped, mid- to dark green, with red veins and serrated edges. The stems are hollow and hairless, and are usually yellow-green tinged with red. Flowers are borne in summer and can be pink, purple or occasionally white, and have an unusual, hooded shape. These are followed by green, kite-shaped seed pods, which are red-tinged. When ripe, the seed pods ‘explode’ and spread the seed as far as seven metres from the parent plant. Himalayan balsam completes its life cycle within one year and dies in autumn.

Is Himalayan balsam a problem?

Himalayan balsam is a problem plant and very invasive in the UK. In many areas the whole ecological balance of the landscape has been altered by Himalayan balsam and it's regarded as a huge problem by ecologists. Its height, ease of spread and density of growth, along with its ability to grow in low light levels, means it rapidly outcompetes native plants. Also, because Himalayan balsam is so popular with bees, it's thought that other plants may receive less pollination as a result. Himalayan balsam also contributes to erosion problems on river banks because growth disappears in winter, leaving bare soil vulnerable to high rainfall events.

Himalayan balsam is not dangerous to people or animals, and indeed, the flowers, foliage and seeds are edible. Use the young leaves and flowers in salads and the older leaves in soups and stews. Seeds are also edible and have a nutty flavour – collect these by carefully putting a paper bag over the ripe pods and gently shaking it so they explode. Wear eye protection when collecting seeds to avoid injury.

Is growing Himalayan balsam illegal?

Himalayan balsam is listed on Schedule 9 of the Wildlife and Countryside Act in England and Wales and it's on the Government's list of Invasive Non-Native Plant Species of special concern. While it's not an offence to have Himalayan balsam already growing in your garden, it is an offence to plant or otherwise cause it to grow in the wild. It's also banned from sale in the UK.

How to prevent Himalayan balsam

Prevent Himalayan balsam returning by removing the plants before the seed ripens. With regular checking and removal of new seedlings, it's possible to completely eradicate Himalayan balsam within a few years.

How to control Himalayan balsam

Himalayan balsam is a shallow-rooted annual and as such is relatively easy and effective to control by hand weeding. However, its abundant and vigorous growth means that controlling it can be a major task. Dispose of cut plant material by burning, or contact your local council if you need to dispose of it. Do not compost Himalayan balsam or put it in your garden or household waste bin, as it's classed as ‘controlled waste’.

How to remove Himalayan balsam

Simply pull up plants before they set seed and check back every few weeks to ensure no more plants have germinated. Larger areas can be strimmed regularly, again, provided this is done before any plants have set seed.

Frequently asked questions

Is Himalayan balsam as bad as Japanese knotweed?

While Japanese knotweed and Himalayan balsam are both invasive non-native plant species, Japanese knotweed is much worse because it's perennial, and the roots are extremely vigorous and wide-spreading.

What to do if you see Himalayan balsam?

On your own land, control Himalayan balsam as soon as you see it. If you see it growing in the wild, inform the landowner, as they may not be aware of its presence. You can help tackle Himalayan balsam by getting involved in local conservation working groups, with special working party days dedicated to Himalayan balsam removal.