Why the Himalayan Balsam is a Noxious Weed
If this ornamental was kept controlled in a flower garden, it would be a welcome addition; however, the plant soon gets out of control because of its clever method of spreading its seeds. As the seed pod grows, the shell segments come under tension. When the pod is ripe and is disturbed, the shell segments roll back in an explosive manner and thereby propelling the seeds over a considerable distance. A garden can soon become overrun with the plant, and eventually it advances to the shoreline of a lake or stream.
With no natural control enemies, the Himalayan Balsam can quickly become the dominant species on a shoreline, displacing other beneficial species. In addition, it has been reported that because of the abundance of sweet nectar, bees and other insects will preferentially pollinate this plant to the detriment of other plants. The shoreline eventually becomes a monoculture, covered with only Himalayan Balsam. Because it does not start growing until July and disappears at the first of October, the shoreline remains bare and unprotected for most of the year. And the shallow root system provides little anchorage to inhibit shoreline erosion.
There are many places where the Himalayan Balsam has completely taken over the landscape. But with a carefully planned and executed program to eradicate this plant, the task can be successful.