Himalayan Balsam (Impatiens glandulifera) is an appealing plant for foragers. Not only are most parts edible but its attractive pink orchid-like flowers make it an easy spot, while its violently exploding seed pods create a curious addition to the UK’s river corridors.
Himalayan Balsam is a relative of the Busy Lizzie and was first introduced to the UK as a cheap garden plant in 1839 (CABI.org). At one time, it was even marketed as “Mr Noisy’s Exploding Plant”, a novelty plant for children (The Independent, 2013). However, it is a successful invasive and has gone on to colonise 23 European countries, as well as being found in the US and New Zealand.
In the UK, it is now naturalised and is a rapid coloniser of river banks. It crowds out native species and causes erosion, as every year its root stock rots once the adult plant is killed by the first Autumn frosts.
It is not hard to identify once fully grown. Its red-tinged stems can grow to over 2m and are found along the bank of water courses, ditches and steams. Those stems bear a passing resemblance to that other much-maligned invasive Japanese Knotweed. Both plants are on the Schedule 9 list of The Wildlife and Countryside Act (WCA) 1981, Section 14(2), which makes it an offence to plant or cause them to grow in the wild.
The hooded pink or white flowers, which appear in the summer months, make this plant difficult to confuse with anything else. They are shaped like an old Policeman's helmet or, when turned upside down, a Persian slipper. Which is where some of its other common names originate.
Himalayan Balsam’s distinctive seed dispersal technique has contributed to its rapid spread. Its seedpods are green droplet-shaped capsules, which will explode at the slightest touch when ripe and can project seeds up to 7m. They are then carried along the waterways to colonise new areas of bank — and with each plant producing up to 800 seeds, which have a germination rate of 80%, it has rapidly become a pest. Since its introduction to the UK, the plant has spread at a rate of 645 km2 per year (Perrins et al., 1993).
Both the pale immature seeds and dark mature seeds, which have a nutty, slightly peppery taste, are edible, and the pods can be cooked whole, like mangetout.
Himalayan Balsam is commonly used in curries in its native India. The young leaves and flowers can be used in salads, while the more bitter, older leaves are more suited to soups and stews. The flowers can also be used to create colour-changing drinks, including gin and lemonade.
However, this plant contains high levels of minerals, as well as calcium oxalate, so consumption should be in moderation.
Responsible foraging is a must, and a bag should be placed over the mature seedpods to catch the seeds when they explode. Extreme care needs to be taken not to disperse the seeds if transporting them home.
Always stay safe when foraging. You need to be 100% sure of your identification, 100% sure that your foraged item is edible, and 100% sure that you are not allergic to it (it is good practice to always try a small amount of any new food you are consuming). If in doubt, leave it out!