28/07/2024
Identifying invasive species.
Himalayan Balsam (Impatiens glandulifera).
The west of Edinburgh is a great place for finding invasive species at this time of year with its many waterways and diverse transport network. I spotted this on the north side of the airport perimeter along the banks of the river Almond. This is actually a very small patch compared to what Iāve seen during a recent trip to Perthshire.
This bad lad of botany doesnāt tend to get the same level of press coverage as its glamorous invasive counterparts Japanese knotweed or Giant Hogweed but still just as destructive to our native habitat and massively efficient in reproduction.
The genus name Impatiens, means āimpatientā, which refers to its method of seed dispersal. The species name glandulifera comes from the Latin words glandis meaning āglandā, and ferre meaning āto bearā, referring to plant bearing glands. It was brought into Europe in the first half of the 19th century as ornamental plant.
The prolific seed production of each Himalayan balsam plant, with more than 2,500 seeds per plant that can remain viable for up to 2 to 3 years, enables easy transportation by water. When the seed pods mature, they burst upon contact, dispersing the seeds up to 7 meters away. This widespread dissemination of Himalayan balsam seeds is proving problematic for landowners and land managers.
Due to its vigorous growth, Himalayan balsam soon dominates and suffocates all other plants within its vicinity. On riverbanks this can cause major problems of erosion.
The lack of natural predators in the UK allows for the rapid establishment of dense colonies of Himalayan balsam, leading to detrimental effects such as a decrease in spider, beetle, and bug species within invertebrate feeding groups. Additionally, the high nectar production of Himalayan balsam may attract pollinating insects at the expense of native flowering plants.
Japanese knotweed is also present in one of the pictures and looks to be making slow progress against the Balsam in this location.