Balsam Blues
The yellow-flowered Touch-me-not Balsam, Impatiens noli-tangere, is a native balsam that grows in damp woods in mid-west Wales and the western edge of the Lake District. Up and down British waterways its non-native cousin the Himalayan Balsam, Impatiens glandulifera,
has 'invaded' and pushed out native undergrowth flowers that support native invertebrates. While we might be hard pushed to go out and find the British plant, the masses of pink/purple flowers on two metre high Himalayan Balsams are in huge swathes and even intruding into many corners of Cornwall. However, it is a time of austerity in the bee world - so is the Himalayan Balsam a sinner or a saviour?
Impatiens glandulifera is an annual plant. Rapid growth, profuse flowering and very effective seed dispersal demand huge resources from the environment, although in return these nutrients do go back into the ground in the winter. During the flowering time, however, the plant produces copious amounts of nectar, and the heavy body weight and strong legs enable the bumble bee to reach the nectaries in the spur at the back of the flower. In competitive terms the Himalayan Balsam is an Olympic champion, but would growing small clumps of well-controlled plants maintain viable propulations of bumble bees until the world wakes up to the plight of rapid loss of bee habitats? Can we risk any further invasion that has been out of control for more than the fifty years with which I am familiar, or can we accept its 'naturalisation' as part of our ever-evolving landscape?
Dr John Bergin
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