Himalayan Balsam ( impatiens glandulifera) is an interesting plant. An annual, with distinctive red veined leaves and large pink flowers, it can grow 2 meters in a single season. When pollinated the plant produces explosive seed pods capable of scattering up to 2500 seeds per plant over a five meter radius.
And this is the problem, the large flowers out compete native species for the attention of pollinating insects and the multitude of seeds soon produce seedlings that blanket the ground. So for these reasons it is classed as a noxious weed and conservationists spend many hours pulling it up. Fortunately this is not difficult, for such a large plant is incredibly shallow rooted.
Interestingly the plant is in fact edible, both leaves and seeds but this fact should come with a government health warning. The plant should not be eaten if you suffer from - a list of ailments as long as my arm - so best not try just in case!
daveb