Friend or Foe?

After yesterday's epic day on Scafell, I didn't have a lot of energy left for finding blips.

At lunchtime I walked to the River Kent from the office in Kendal. The long dry spring provided ideal conditions for Himalayan Balsam seeds to germinate and establish along the river's edge.

The flowers were buzzing with bumblebees, honey bees and hoverflies like this one. Yet this annual plant is one of the hated invasive weeds that are established on our river banks, supposedly outcompeting our native flora. The green pods, when ripe, explode when touched, flinging their seeds away up to 7 metres from the parent plant, thereby dispersing it to invade fresh ground. Doubtless many seeds are carried downstream to settle out on the riverside further downstream.

This "touch-me-not" species is undoubtedly a beautiful plant which provides welcome nectar to insects at this time of the year. One definition of a weed is "a plant in the wrong place". Here in Britain, far from its native Himalayas, Impatiens glandulifera is just that - alas.

There is an alternative photo on Flickr that shows the structure of the flower in more detail.