If you thought Devil’s Snare — the creepy plant from Harry Potter that wraps around and kills anything it comes into contact with — was bad, another real-world creeper might be worse (if not as deadly). Himalayan Balsam is an invasive plant rapidly spreading across the world, one exploding seed pod at a time.
Himalayan Balsam, as its name suggests, is an annual plant native to the Himalayas. It’s been introduced to other parts of the world, as many plants are, because of its aesthetic appeal. So far Himalyan Balsam has spread to the United Kingdom, Ireland, and even the United States in the last few decades.
The problem with Himalayan Balsam is that, while nice to look it, it’s an aggressive invasive species. It can rapidly take over damp areas like river beds, muscling out native plants until it’s the only one in the area. And here’s where the explosions come in.
A full-grown plant can be more than six feet tall, sporting pink slipper-shaped flowers. After the plant flowers, it develops pods that are filled with sticky seeds. When those pods are disturbed, say, by a curious person walking along a colonized river bed, they rupture, shooting the seeds out in all directions. And the explosion is incredibly robust; seeds from one pod can cover as much as 23 feet (7 meters).
Because the seeds are so forcefully ejected, they spread far and wide. Imagine a whole river bed covered with exploding seed pods (where one explosion could trigger others). It’s easy to imagine how the plants could colonize a massive area in just a few years and become a real problem. They have. Because Himalayan Balsam forces out native vegetation and is dormant in the winter months, the plant leaves vast tracts of land exposed to harsh winters, inviting problems like frosts and landslides.
There’s a push among scientists to somehow stem the spread of this plant, but it’s a challenge. Himalayan Balsam is pretty insistent on spreading as far and wide as possible. Its Latin name, Impatiens glandulifera, speaks to its impatience to get its roots in new places all the time. Having such a fascinating seed dispersal mechanism is probably a big part of why the balsam is so good at conquering ground, but it also could just be better evolved than those it conquers.
So if you come across Himalayan Balsam, don’t disturb the pods. Not only will you help it spread, you might get shot in the face with a seed cannon.
Feature Image credit Amy Lewis via Scottish Wildlife Trust