myotis said:
Looks more like Impatiens tinctoria to me. Is this in the wild or in a garden/park etc.
If it is I. tinctoria, then it's not invasive (ie doen't seed around like it's annual and obviously loathed relative), perennial, just about hardy and a magnificent addition to any garden scheme if you want that jungle look!
As others have said, it is
Himalayan (or 'Indian')
Balsam,
Impatiens glandulifera. Although we don't have a close-up photograph, the upper petals are visible and they are much too large for
I. tinctoria. Sorry.
It is invasive, but I am not sure that it is a significant threat to our native species. It is very shade tolerant and can grow in wet, open ground in dark woodland - typically in places that are not used much by other species anyway. It can be dominant on riverbanks, especially after disturbance or where there is some organic pollution, but again my impression is that it is finding a niche that is otherwise not being greatly exploited. Yes, it must be displacing other plants, but I am not sure what.
Potentially it is a theat to nationally scarce species such as
Scrophularia umbrosa (Green Figwort), but most of our local colony of the latter vanished not through competition from the Balsam, but from the local council putting up a notice, "Environmental Improvement", and promptly destroying it.
My main objection to Himalayan Balsam is that the scent of large colonies can be pretty overpowering - rather like massed, over-ripe strawberries.
As Neil says, bumble bees like it! (Proof attached, though both the flower and the bee seem to have had rough times!)
Alan